I am experiencing the same issue, the issue showed up after I moved my avatar projects to another folder on the same drive.

Can confirm here i have same problem.

This happens only if you re-use backups from VCC (you made backup from appdata), usually done if you want do new Windows install. But after install, drive letters also changed and that cause the VCC code thinks it's invalid.

Due poor code check routines, it throws already error before you can select the map.

That is because in my case the project location is set on drive I: but after fresh install it changed to G:.

The button "Pick New Folder" also throw quickly the error. That is weird because here i can correct the error by select new correct project map to solve the problem here.

Due wrong coding in VCC checks, it checks FIRST for project map, and it see it doesn't exists, it will refuse automatically.

I suggest add code in check routing to revert to default C: if project doesn't exists. Especially if i click on Pick New Folder, it must let me choose new map, but VCC is too stubborn to let me choose it.

This is clearly code mistake. You need remove it, add extra step to 'reset' itself to C: drive (auto-reset to default map for VCC) then i can select new project map. Most programs have this option, but developers VCC just forgot we make backups too, we do sometimes new Windows installs, and put back backup works, but VCC cannot fix itself and stay stubborn, without any chance to correct the Project location. That is not good.

Please fix this problem. I go fix it manually in settings to change project map by myself.

Go to AppData\Local\VRChatCreatorCompanion\. You see settings.json file there. Change in your editor "defaultProjectPath" to correct one. It can find already above on first rows. After save it, i can add existing projects.

Weird enough, "projectBackupPath" is correct set in settings. How come VCC cannot just see it? Because the code lacked some steps to fix itself.

I should add, this is version 2.4.1 and on the latest Windows 11. Also if I revert to an older version of creator companion it works again and then if I upgrade back to the latest it breaks again.

I'm unable to reproduce the bug on mine

Example video. As you can see, it does not even give you the option to select a directory like it should. It just immediately errors out.

Reinstalling the CC does not seem to correct the issue.