While reading through the code, I noticed the comment about RiME's paths and using path.join. I figured out what's wrong (rime has an absolute path) and handled that case.
Not sure if this would actually handle any case better, but using path.join is how you'd expect to write it, so maybe this is preferable.
Test
Install RiME via EGS, run steamsync, restart steam, run rime.
While reading through the code, I noticed the comment about RiME's paths and using path.join. I figured out what's wrong (rime has an absolute path) and handled that case.
Not sure if this would actually handle any case better, but using path.join is how you'd expect to write it, so maybe this is preferable.
Test Install RiME via EGS, run steamsync, restart steam, run rime.