[Solved] Lightroom "An error occurred when attempting to change modules." on launch.

I just spent a few days and time with Adobe support attempting to solve this to no avail, and finally stumbled upon the solution so I'm putting it here in case anyone else encounters it.

Before I explain, here is the Adobe guide for solving the "changing modules" issue. This was of no use to me but may be for you.

Here is the article that solved the issue. Troubleshoot User Account Permissions

Downloading the script "LightroomCorrectPermission.zip" and running it as described solved the issue immediately. It also solved a little (non-critical) error message that Lightroom Classic was throwing.

What's strange is that I had already set permissions for all relevant folders accordingly. That was probably among the first 10 or so things I did attempting to solve this without any success. I checked all permissions after running the script and all settings appear the same, so I have no explanation as to why this helped.

For the record, this issue occured on Mac OS Monterey Version 12.1 and Lightroom Version 5.1

Hopefully someone else can save a few shreds of their own sanity with this post.