NordicSemiException: Serial port could not be opened...solution found

Following this page[ https://wiki.seeedstudio.com/XIAO-BLE-Sense-Bluetooth_Usage/#tech-support--product-discussion] which is titled "Bluetooth Usage (Seeed nRF52 Boards Library)"

Using Arduino IDE 2.3.2, XIAO nRF52840, Example sketch Files>Examples>Adafruit Bluefruit nRF52 libraries>peripheral> blehid_keyboar.ino

Trying to upload this sketch produces these errors:

_Library Adafruit nRFCrypto has been declared precompiled: Using precompiled library in c:\Users\occam\Documents\Arduino\libraries\Adafruit_nRFCrypto\src\cortex-m4\fpv4-sp-d16-hard Sketch uses 125524 bytes (15%) of program storage space. Maximum is 811008 bytes. Global variables use 14880 bytes (6%) of dynamic memory, leaving 222688 bytes for local variables. Maximum is 237568 bytes. Upgrading target on COM18 with DFU package C:\Users\occam\AppData\Local\Temp\arduino\sketches\9F5A3A7B965D41E83025B90A6720C1ED\blehid_keyboard.ino.zip. Flow control is disabled, Single bank, Touch disabled

Failed to upgrade target. Error is: Serial port could not be opened on COM18. Reason: could not open port 'COM18': FileNotFoundError(2, 'The system cannot find the file specified.', None, 2) Traceback (most recent call last): File "dfu\dfu_transport_serial.py", line 113, in open File "serial\serialwin32.py", line 33, in init File "serial\serialutil.py", line 244, in init File "serial\serialwin32.py", line 64, in open serial.serialutil.SerialException: could not open port 'COM18': FileNotFoundError(2, 'The system cannot find the file specified.', None, 2)

During handling of the above exception, another exception occurred:

Traceback (most recent call last): File "main.py", line 296, in serial File "dfu\dfu.py", line 235, in dfu_send_images File "dfu\dfu.py", line 157, in _dfu_send_image File "dfu\dfu_transport_serial.py", line 115, in open nordicsemi.exceptions.NordicSemiException: Serial port could not be opened on COM18. Reason: could not open port 'COM18': FileNotFoundError(2, 'The system cannot find the file specified.', None, 2)

Possible causes:

Selected Bootloader version does not match the one on Bluefruit device. Please upgrade the Bootloader or select correct version in Tools->Bootloader.
Baud rate must be 115200, Flow control must be off.
Target is not in DFU mode. Ground DFU pin and RESET and release both to enter DFU mode._

Solution is to select: Tools>programmer>Bootloader DFU for Bluefruit nRF52

You should now see this: ....###### Activating new firmware Device programmed.

Dear Seeed support: Please review and update webpage to prevent more grey hair :-)

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NordicSemiException: Serial port could not be opened...solution found #1671