regdmp has access denied

[ajrgodfrey]

I've got R v4.2.0 and Quarto downloaded this week. When I run quarto check in the Windows command prompt, I get an error that regdmp cannot fetch the hkey_local_machine... relevant to the R installation. I can open regedit and see that the desired path regdmp is looking for is there, and that it contains the right install path for R, but the "access denied" message is stopping me in my tracks. What shoudl I try next?

[jjallaire]

I just made a change that reads HKCU before HKLM when attempting to detect R (this is the same order that RStudio uses when detecting R): https://github.com/quarto-dev/quarto-cli/commit/966fd980313795e7f995b0b1098657821e417bd5

This change is available in v0.9.624: https://github.com/quarto-dev/quarto-cli/releases/tag/v0.9.624

@ajrgodfrey It would be helpful if we could see the entire output of quarto check (including the registry error)

@cderv Have you ever seen anything like this?

[ajrgodfrey]

Output from quarto check install and quarto check knitr:

[>] Checking Quarto installation......OK Version: 0.9.624 Path: C:\PROGRA~1\Quarto\bin\ CodePage: 1252 (|) Checking basic markdown render.... (/) Checking basic markdown render.... (-) Checking basic markdown render.... (\) Checking basic markdown render.... (|) Checking basic markdown render....[2K[G [>] Checking basic markdown render....OK (|) Checking R installation........... (/) Checking R installation...........REGDMP: Unable to open key 'HKEY_LOCAL_MACHINE\SOFTWARE\R-core\R' (2) Access is denied. [2K[G [>] Checking R installation...........(None) Unable to locate an installed version of R. Install R from [1mhttps://cloud.r-project.org/[22m Above captured as part of processing an Rmd file with shell() commands in chunks, processed with R4.2.0 outside RStudio. So no change with 0.9.624 I will need eyes to help prove RStudio has found R on the same machine; 7 hour delay on that. Jonathan From: J.J. Allaire ***@***.***> Sent: Monday, 27 June 2022 12:26 am To: quarto-dev/quarto-cli ***@***.***> Cc: Jonathan Godfrey ***@***.***>; Mention ***@***.***> Subject: Re: [quarto-dev/quarto-cli] regdmp has access denied (Issue #1225) I just made a change that reads HKCU before HKLM when attempting to detect R (this is the same order that RStudio uses when detecting R): 966fd98 This change is available in v0.9.624: https://github.com/quarto-dev/quarto-cli/releases/tag/v0.9.624 @ajrgodfrey It would be helpful if we could see the entire output of quarto check (including the registry error) @cderv Have you ever seen anything like this? - Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you were mentioned.Message ID: ***@***.***>

[cderv]

@cderv Have you ever seen anything like this?

@jjallaire I believe this could be linked to Windows User Access Control (UAC) mechanism. Reading registry key can require some specific privilege. Restriction seems to be per key or Usually on some computer (like mine), using regedit program will asked for elevated privileges. It seems there is specific behavior on application (e.g this https://docs.microsoft.com/en-us/cpp/security/how-user-account-control-uac-affects-your-application), and regedit must be aware and ask.

I don't remember having encounter such issue in my test, so it may not be something that applies everywhere. Like this works fine for me in Terminal with Deno without elevated privileged:

❯ Deno
Deno 1.23.1
exit using ctrl+d or close()
> const cmd = ['reg', 'query', 'HKLM\\Software\\R-core\\R', '/v', 'Current Version']
undefined
> const p = Deno.run({cmd})
undefined
>
HKEY_LOCAL_MACHINE\Software\R-core\R
    Current Version    REG_SZ    4.2.0

So I don't have trouble reading. Same with R.

> utils::readRegistry("Software\\R-core\\R", "HLM")
$`Current Version`
[1] "4.2.0"

$InstallPath
[1] "C:\\Program Files\\R\\R-4.2.0"

$`4.1.2`
[1] "<subkey>"

$`4.2.0`
[1] "<subkey>"

So no change with 0.9.624

It seems the fix you've made did not change anything, so it is probably something related to access control, or Just R is not in the registry.

@ajrgodfrey

• Are you using a windows environment with any type of restriction, like controlled by your company or else ?
• Also if you are an R user can you try utils::readRegistry("Software\\R-core\\R", "HLM") ?
• Can you run in Windows Command terminal (CMD) this REG QUERY HKLM\Software\R-core\R ?
• In powershell that would be Get-ItemProperty -Path "HKLM:\Software\R-core\R"

This is to see if the reading of registry is blocked also for other tools ?

If you have a UAC windows popping asking to give higher privileges, this will be interested to us.

Also if you are willing to gets your hand into this, it would be interesting to really check the permissions of this keys we are trying to read. Step would be:

1. Type Windows Key + R - A execute windows will open
2. Type regedit and click Enter. Either you can't at all if this is blocked on your computer by whoever is the admin, or a UAC window will open asking you to give higher privileges.
3. If you can open, you'll be able to look for keys . In the new window, click on the root and then append \HKEY_LOCAL_MACHINE\SOFTWARE\R-core\R to see if you can read this key. (You can also open folder in the tree to get to this value.

Thanks for your help.

BTW @jjallaire, this will probably also affect chrome research that uses also a registry mechanism (a fix should be apply there too as it is not using the same function) https://github.com/quarto-dev/quarto-cli/blob/966fd980313795e7f995b0b1098657821e417bd5/src/core/puppeteer.ts#L211-L239

[ajrgodfrey]

@cderv provided tests/questions.

Questions:

• Are you using a windows environment with any type of restriction, like controlled by your company or else ? A: It is a university controlled machine but I generally have admin privileges; freedom to install/remove software at admin level.

• Is UAC present?

A: yes, I must elevate to admin to view regedit. I can traverse the folder tree and see the full path, and the Current version and InstallPath variables.

Test results:

In R: utils::readRegistry("Software\R-core\R", "HLM") Result: total success

In windows cmd prompt: REG QUERY HKLM\Software\R-core\R Result: total success

Where I count finding the path to the R installation to be success. My results are the same as yours, but only one version of R is present.

BTW: I have used regdmp successfully before now in an unrelated R workflow. I create shortcuts to a batch file that looked across installed versions to find the latest one on any given system so that I could make sure all teaching resources remained unproblematic as R versions came and went. That tool worked with R v4.1.3 but is now broken for v4.2.0 in that it cannot see it. I have removed all versions of R < 4.2.0 though but would reinstall an older one if that will help testing.

Jonathan

[cderv]

Thanks a lot for the test. This is helpful. It seems that you can read the registry key, except that Quarto does not.

To confirm this, can we try reading the registry within Deno runtime ?

1. Go into quarto install directory where the binaries are to find a deno executable

   • Should be in quarto install folder bin/tools
   • In powershell with Quarto in PATH, I can get there with "$((Get-Command quarto).Source)/../tools" but it depends if you have quarto in PATH.
   • Anyway, you can just go into this folder in file explorer and open a terminal in this folder <quarto_install_path>/bin/tools
     2. Run deno in terminal by typing deno
     3. Try to read the registry as I did

        const cmd = ['reg', 'query', 'HKLM\\Software\\R-core\\R', '/v', 'Current Version']
        const p = Deno.run({cmd})

2. Use CTRL+D to quit and close

This is what I get

❯ Deno
Deno 1.23.1
exit using ctrl+d or close()
> const cmd = ['reg', 'query', 'HKLM\\Software\\R-core\\R', '/v', 'Current Version']
undefined
> const p = Deno.run({cmd})
undefined
>
HKEY_LOCAL_MACHINE\Software\R-core\R
    Current Version    REG_SZ    4.2.0

Aim is to see if Deno have issue to read the registry, or if this is something really inside Quarto code base and our usage.

Thanks for your help.

[jjallaire]

@cderv One interesting thing is that our Deno code as currently structured shouldn't be throwing an error when it can't read a key (it should just return undefined and move on). It makes me think there is some sort of external security/supervisory software running that is observing the read and terminating the program.

Note that another way to test out various scenarios in an isolated fashion here is for us to write a script that is executed by our quarto run command: https://quarto.org/docs/projects/quarto-projects.html#project-scripts

[cderv]

Thanks! I forgot about this way to run TS script.

@ajrgodfrey easier way to see what Deno reading registry tells us

Put this into a test.ts file

const cmd = ['reg', 'query', 'HKLM\\Software\\R-core\\R', '/v', 'Current Version']
const p = Deno.run({cmd, stdout: "piped", stderr: "piped"})
const { code } = await p.status();
// Reading the outputs closes their pipes
const rawOutput = await p.output();
const rawError = await p.stderrOutput();
if (code === 0) {
  await Deno.stdout.write(rawOutput);
} else {
  const errorString = new TextDecoder().decode(rawError);
  console.log(errorString);
}
Deno.exit(code);

and then call

quarto run test.ts

This would help us understand when running reg.exe in Deno returns.

[ajrgodfrey]

Instructions complete and helpful 😊

The test.ts script (as provided) returns the current version number of R as required. I ran this in the cmd prompt.

The outcome has four lines between prompts. First line has plenty of white space; second line has the hkey, followed by some white space; third line has white space, “Current Version”, white space, “REG_SZ”, white space, “4.2.0”, and more white space. Fourth line is lots of white space.

Notes:

• Quarto check knitr then fails to find R, as before.
• I could not pipe the outcome from the script processing to a log file using > log.txt, or at least the log file is blank. This is my preferred way to capture output from any cmd task.

Naïve question: where/how is the outcome from the test.ts script supposed to be captured?

My attempt to help:

Looks like I need to try the next part of the job to see why the installation path isn’t picked up. Looking at my registry using regedit, I see two places. InstallPath is in parallel to the Current Version, and a subfolder for v4.2.0 has the same information under it.

If I replace the first line of your script with const cmd = ['reg', 'query', 'HKLM\\Software\\R-core\\R', '/v', 'InstallPath'] I get The same four lines and two more. Current version is replaced by InstallPath and delivers correct outcome, but I then get a line starting with “Check file:” and the path to my script file.

If I change the first line of the script to const cmd = ['reg', 'query', 'HKLM\\Software\\R-core\\R\\4.2.0', '/v', 'InstallPath'] I get the exact same outcome.

HTH Jonathan

[cderv]

The test.ts script (as provided) returns the current version number of R as required. I ran this in the cmd prompt.

The outcome has four lines between prompts. First line has plenty of white space; second line has the hkey, followed by some white space; third line has white space, “Current Version”, white space, “REG_SZ”, white space, “4.2.0”, and more white space. Fourth line is lots of white space.

This means that registry can be read from Deno run within Quarto. This is the same command as within Quarto so I don't know what is going one here.

using regedit, I see two places. InstallPath is in parallel to the Current Version,

The workflow is to read "Current Version" first, then query "InstallPath" to get the actual path.

I still don't manage to reproduce this behavior. I'll see if I can come up with another test to run to get more information.

Looking at my registry using regedit, I see two places.

In regedit, at the keys, can you check if there are specific permissions ?

Should be possible to see by using right-click the directory or keys, and then click Permissions.... You should be able to see if somehow this looks like default or have specific restricition.

Also, how did you install R by the way ?

[jjallaire]

My other theory is that there is some anti-malware or anti-virus software on the system that sees quarto attempting to read from HKLM and terminates it (this would be consistent w/ the fact that the code we have that reads the registry isn't supposed to throw or even print an error). Is that a possibility?

[cderv]

I proposed a change in https://github.com/quarto-dev/quarto-cli/pull/1234, this won't solved but I believed your change in https://github.com/quarto-dev/quarto-cli/commit/966fd980313795e7f995b0b1098657821e417bd5 made this issue surfaced.

Regarding the anti malware, or anti virus, I don't know for sure. I understand that @ajrgodfrey environment is controlled but quite flexible. I'll have a look at Windows defender to see if it can block quarto binary.

[cderv]

@ajrgodfrey as another test regarding priviledges, you could try running quarto check knitr in an elevated terminal (usually right click on the program like your terminal, or CMD and choose exectute as administrator. As you said you have admin access, we could see if this solve the "access denied"

Maybe looking at permissions in registry would help see a non default setting.

Regarding quarto being being block, maybe Security Event Logging on windows can help see that (https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/view-the-security-event-log) but this is hard to find one specific to quarto. Maybe run quarto check knitr and then look at the log ?

Do you have a malware software on your computer by the way ?

[cderv]

Last thing @ajrgodfrey, I wrote this script to isolate what Quarto is doing. If this throws the same issue this could help us debug further. But the questions above regarding potential anti-malware software are the next trail to follow.

Note: update to latest quarto in your next tries BTW

quarto run full-search.ts

full-search.ts

````typescript import { MuxAsyncIterator, pooledMap, } from "https://deno.land/std/async/mod.ts"; import { iterateReader } from "https://deno.land/std/streams/mod.ts"; import { info } from "https://deno.land/std/log/mod.ts"; export interface ProcessResult { success: boolean; code: number; stdout?: string; stderr?: string; } export async function execProcess( options: Deno.RunOptions, stdin?: string, mergeOutput?: "stderr>stdout" | "stdout>stderr", stderrFilter?: (output: string) => string, ): Promise { // define process try { // If the caller asked for stdout/stderr to be directed to the rid of an open // file, just allow that to happen. Otherwise, specify piped and we will implement // the proper behavior for inherit, etc.... const process = Deno.run({ ...options, stdin: stdin !== undefined ? "piped" : options.stdin, stdout: typeof (options.stdout) === "number" ? options.stdout : "piped", stderr: typeof (options.stderr) === "number" ? options.stderr : "piped", }); if (stdin !== undefined) { if (!process.stdin) { throw new Error("Process stdin not available"); } // write in 4k chunks (deno observed to overflow at > 64k) const kWindowSize = 4096; const buffer = new TextEncoder().encode(stdin); let offset = 0; while (offset < buffer.length) { const end = Math.min(offset + kWindowSize, buffer.length); const window = buffer.subarray(offset, end); const written = await process.stdin.write(window); offset += written; } process.stdin.close(); } let stdoutText = ""; let stderrText = ""; // If the caller requests, merge the output into a single stream. This single stream will // follow the runoption for that stream (e.g. inherit, pipe, etc...) if (mergeOutput) { // This multiplexer that holds the async streams and merges their results const multiplexIterator = new MuxAsyncIterator< Uint8Array >(); // Add streams to the multiplexer const addStream = ( stream: (Deno.Reader & Deno.Closer) | null, filter?: (output: string) => string, ) => { if (stream !== null) { const streamIter = filter ? filteredAsyncIterator(iterateReader(stream), filter) : iterateReader(stream); multiplexIterator.add(streamIter); } }; addStream(process.stdout); addStream(process.stderr, stderrFilter); // Process the output const allOutput = await processOutput( multiplexIterator, mergeOutput === "stderr>stdout" ? options.stdout : options.stderr, ); // Provide the output in whichever result the user requested if (mergeOutput === "stderr>stdout") { stdoutText = allOutput; } else { stderrText = allOutput; } // Close the streams const closeStream = (stream: (Deno.Reader & Deno.Closer) | null) => { if (stream) { stream.close(); } }; closeStream(process.stdout); closeStream(process.stderr); } else { // Process the streams independently if (process.stdout !== null) { stdoutText = await processOutput( iterateReader(process.stdout), options.stdout, ); process.stdout.close(); } if (process.stderr != null) { const iterator = stderrFilter ? filteredAsyncIterator(iterateReader(process.stderr), stderrFilter) : iterateReader(process.stderr); stderrText = await processOutput( iterator, options.stderr, ); process.stderr.close(); } } // await result const status = await process.status(); // close the process process.close(); return { success: status.success, code: status.code, stdout: stdoutText, stderr: stderrText, }; } catch (e) { throw new Error(`Error executing '${options.cmd[0]}': ${e.message}`); } } export function processSuccessResult(): ProcessResult { return { success: true, code: 0, }; } function filteredAsyncIterator( iterator: AsyncIterableIterator, filter: (output: string) => string, ): AsyncIterableIterator { const encoder = new TextEncoder(); const decoder = new TextDecoder(); return pooledMap(1, iterator, (data: Uint8Array) => { return Promise.resolve( encoder.encode(filter(decoder.decode(data))), ); }); } // Processes ouptut from an interator (stderr, stdout, etc...) async function processOutput( iterator: AsyncIterable, output?: "piped" | "inherit" | "null" | number, ): Promise { const decoder = new TextDecoder(); let outputText = ""; for await (const chunk of iterator) { if (output === "inherit" || output === undefined) { info(decoder.decode(chunk), { newline: false }); } const text = decoder.decode(chunk); outputText += text; } return outputText; } export const kHKeyCurrentUser = "HKCU"; export const kHKeyLocalMachine = "HKLM"; export async function registryReadString( root: string | string[], key: string, value: string, ): Promise { // if an array is passed then call each one in turn if (Array.isArray(root)) { for (const r of root) { const val = await registryReadString(r, key, value); if (val !== undefined) { return val; } } return undefined; } // run reg query console.log(`Searching in ${root} for ${key}`) const kTypeString = "REG_SZ"; const cmd = [ "reg", "query", `${root}\\${key}`, "/v", value, ]; const result = await execProcess({ cmd, stdout: "piped", stderr: "null", }); console.log(result) if (result.success && result.stdout) { const typePos = result.stdout?.indexOf(kTypeString); if (typePos !== -1) { return result.stdout.substring(typePos + kTypeString.length).trim(); } } return undefined; } const version = await registryReadString( [kHKeyCurrentUser, kHKeyLocalMachine], "Software\\R-core\\R", "Current Version", ); console.log(version) ````

My output

```` Searching in HKCU for Software\R-core\R { success: false, code: 1, stdout: "", stderr: "Erreur�: Erreur�: le syst�me n'a pas trouv� la cl� ou la valeur de Registre sp�cifi�e.\r\n" } Searching in HKLM for Software\R-core\R { success: true, code: 0, stdout: "\r\nHKEY_LOCAL_MACHINE\\Software\\R-core\\R\r\n Current Version REG_SZ 4.2.0\r\n\r\n", stderr: "" } 4.2.0 ````

[ajrgodfrey]

Elevated privileges on cmd: test results are unchanged

I have just re-installed R as administrator (paranoia) and all tests undertaken thus far are returning the exact same outcomes.

I would normally install R using all defaults, and not normally as administrator. This is so that my experience matches those of my students.

Checking permissions via regedit: full control for administrators and read access for all users. There is a "deny access" check box that is unticked. I assume don't deny = allow.

Malware protection: none in play aside from Windows Defender.

Theory: we have not tested the full workflow outside quarto to find the path; we know that the first step works to find the current version number. We do not know which step of the quarto process is giving me the Access Denied error.

Full search script: I put everything from import to the final } in a script file but I get an error when I ran it. It is of the bad syntax kind, not anything to do with what we're trying to resolve. I am not at all familiar with the ts language so I can't sort that out. It says my file is missing a ; } or

[cderv]

Here is the script in a zip file, which is working for me using quarto run and latest quarto full-search.zip

We do not know which step of the quarto process is giving me the Access Denied error.

The idea is to find where in the code the error happens. However, from your error

.REGDMP: Unable to open key 'HKEY_LOCAL_MACHINE\SOFTWARE\R-core\R' (2)

The key searched is the one for the R version number. So it seems for some reason it can't be read.

Malware protection: none in play aside from Windows Defender.

I'll see if Windows Defender has a mechanism to block some program.

[ajrgodfrey]

Script ran successfully.

Check in HKCU was false (as expected)

Check in HKLM was true (as should be) and returned 4.2.0

Q: Given the script found the version number, surely it could find the InstallPath that is right beside it? From what I'm reading, the quarto process is to use that current version number to find the path for that version. That seems to use two steps when only one is necessary, or am I missing something?

Btw: I keep checking for changes to quarto, so now I have tried everything using 0.9.629 and I still have the same test results.

[cderv]

Q: Given the script found the version number, surely it could find the InstallPath that is right beside it? From what I'm reading, the quarto process is to use that current version number to find the path for that version. That seems to use two steps when only one is necessary, or am I missing something?

Here is the full script equivalent to what we are running inside Quarto full-search.zip

I added the path search for the version found.

If this is working, it really seems to be a permission issue, where somehow quarto binary is blocked on your system regarding registry.

[ajrgodfrey]

Results are the same. HKCU is false and HKLM is true, returning the correct R version number.

[cderv]

Results are the same. HKCU is false and HKLM is true, returning the correct R version number.

So the correct R path is found ? You should have some logging in the console with R version, R path used and R binary used.

This is all correct on your side ? You can share stdout here.

[ajrgodfrey]

Yes. It shows me the full path to Rscript (without the .exe)

I checked the quarto check knitr again and it still throws the access denied error.

[cderv]

Unfortunately, I really don't know what is going one here.

Yes. It shows me the full path to Rscript (without the .exe)

If the script I sent you is working, it means the TS code executed with the deno runtime inside Quarto can access the registry keys.

Checking permissions via regedit: full control for administrators and read access for all users. There is a "deny access" check box that is unticked. I assume don't deny = allow.

Malware protection: none in play aside from Windows Defender.

It does not seem you have some specific restrictions - I can't find any documentation regarding Windows Defender being able to block registry reading for one app. You can try looked into the setting of Windows defender to see if you find something.

Apart from that, I see only the Users Policies that could be in place on your environment. If you have IT support, maybe you can ask them ? Maybe there is an anti malware on your system provided by your controlled environment and that you are not aware of ?

I am running out of ideas from what could be wrong on our side. It seems to be external from quarto and something is preventing it to run.

I checked the quarto check knitr again and it still throws the access denied error.

Can you share again the whole results of quarto check knitr ?

If the R version can't be found in registry, the last resort is to look for R in ProgramFiles where it should be installed. But it seems it does not even go to this step, and quarto exit with error. Can you confirm that ?

FWIW, workaround to make Quarto works for you is to provide R version ahead of registry look up. This means 👍

1. setting QUARTO_R environment variable,
2. or setting R_HOME (which should be used if you are using quarto within RStudio IDE)
3. or Adding R to your PATH

On windows, there is 2 more steps:

5. If none of the above contains R, then information is searched for in the Registry. This is where you have the issue
6. If all of the above did not work, R is looked for in ProgramFiles - this should work for you, but it seems quarto is erroring before at above step.

Can you share again the quarto check knitr console output ?

[ajrgodfrey]

And perhaps I have found the problem.

I believe when quarto was calling regdmp, that it used a version I had in another folder on the search path.

I removed the regdmp utility from my personal folder that is on the system path, rebooted, and hey presto, quarto can find R!

I don’t know how to check the version of regdmp I had but if it was doing something different to the quarto version, then maybe it is the fault.

I did get asked if I was running a 32 bit version of regdmp, but I can’t tell that either, except by age of the file.

I suggest making quarto use a specific installation of regdmp within quarto via a fully specified path to it, or removing the need for it at all.

Thanks for the help. I think this issue can now be closed.

Jonathan

[jjallaire]

@cderv I noticed that we have two functions which call the registry -- one calls "reg" and one calls "reg.exe". Nowhere do I see "regdmp" called. Is it possible that there is a difference between "reg" and "reg.exe" and one of them calls "regdump" ?

[cderv]

I removed the regdmp utility

@ajrgodfrey you mean regdmp.exe ?

Is it possible that there is a difference between "reg" and "reg.exe" and one of them calls "regdump"

Until last answer from @ajrgodfrey, I assume REGDMP in the error message was just the way reg.exe was erroring when not working. Now that I understand this is another executable, it is possible that reg without extension could be partially matched to regdump.exe instead of reg.exe by Deno.run ?

It seems a bit odd - regdmp.exe does not have a query command. I would assume the error would be different as we are calling reg query. I can't test though as I don't have regdmp.exe on my Windows.

Maybe reg query is calling regdmp.exe in the process when found and this is causing the issue.

But all our test above with quarto run and a .ts file containing Deno.run on "reg" (not reg.exe) and are working fine. Only when quarto render it was causing issues.

@ajrgodfrey is this easy to test again to reproduce the issue if we do change "reg" to full filename "reg.exe" ?

I noticed that we have two functions which call the registry

Yes we have some possible refactoring that you wanted to postpone to v1.1 when I mentioned it (https://github.com/quarto-dev/quarto-cli/pull/1051#issuecomment-1145831117). I assume calling reg and reg.exe was the same, it would not make a difference. but maybe it is.

[ajrgodfrey]

Sure, I'd like to help where I can. I will try, but you will need to suggest tests to run.

FWIW: I moved regdmp.exe to a different location so I could move it back.

Q: Once quarto has found an R installation, does it store its settings anywhere or does it search again each time R is required? If the settings are stored, how often will it look to update the settings?

BTW: I have now moved to quarto 0.9.644 and I keep updating every day or two. I haven't kept all the different installers though.

Jonathan

[ajrgodfrey]

Hello again.

I discovered that regdmp wasn’t working in other circumstances and found a way to avoid having to use it. Perhaps my solution could be looked at for providing a simpler way to find an R installation in quarto as well.

My batch file that opens the current version of R using a terminal is now as follows:

@echo off FOR /F "skip=2 tokens=2,*" %%A IN ('reg.exe query "HKlm\Software\R-core\r" /v "InstallPath"') DO set "InstallPath=%%B" "%InstallPath%\bin\x64\rterm.exe" --save It used to have regdmp doing its magic, but the above looks considerably simpler than my old approach. N.B. I know this only works because I have installed R as an administrator. I’m afraid it has solved my other problems though, and not the subject of this particular thread. I would hope that searching for the above, and for the HKCU key would give a result that is of use. HTH, Jonathan