Before making any of the modifications below, always quit Plex server completely.
This includes the ‘Plex Update Service’!
Take a look at Resetting NTFS files permission in Windows – Graphical Utility – lallous' lab for the ‘permissions’ issue.
@rbeatse said:
Is there a better way? Like restoring a backup? I will try anything at this point.
I’d make a backup copy of the registry branch.
Then delete it and perform a fresh installation. With all settings at default values.
Give it a small collection of media, so you can verify it is at least matching media and transcoding is working.
Only after that, try rerouting the Plex data folder.
Here is the step-by-step guide for that: https://forums.plex.tv/discussion/comment/851746/#Comment_851746
If you managed to do that successfully, create another backup of the registry branch - just in case.
Then exchange the plex data folder by switching the names of the folders, so plex now “sees” your backup.
Then take a look at your oldest registry backup. There should be 3 keys in there with identifier in their name, put these back into the registry. These will re-enable your old Plex friends.
Only try to manipulate the registry if you’ve already done that a few times!
I followed all of the steps and, surprisingly, I did not lose the connections. Everything else worked just as you said it would. You have no idea how relieved I am.