Jellyfin 10.8.11 upgrade failed

[jw2k_fr]

I was running 10.8.9 and decided to upgrade to 10.8.11 to see whether that helped with poor transcoding performance.

Running Windows 11 Pro 22H2 build 22621.2361 (clean install) 
Jellyfin server 10.8.9

Went to run an in-place upgrade, and the installer recognized that I had an existing install and said all settings would be preserved etc.  However, install failed fairly early on due to a locked file and seemed like it was 'done' with things.  Only button I could press was cancel, which I assumed would roll back the upgrade - so I hit cancel, ran a couple of Windows updates and rebooted in order to clear the file lock.

After rebooting, the same 10.8.11 installer did not tell me that I had an existing install and asked me whether I wanted a basic or advanced install, at which point I nixed the install as I did not want to lose my original settings and database.

I used the windows RUN command to look at the %APPDATA% folder and couldn't find a jellyfin settings folder - ditto anything under 'program files', so I would I be right in assuming that the installer crashed having deleted ALL of my settings (rather than backing them up as I would have expected) and that I have now lost the countless hours that I've spent downloading cover art, tweaking display names, dealing with problem child movies and everything else?!?!? <%APPDATA%>/jellyfin, 

[TheDreadPirate]

Your database should be located in C:\ProgramData\Jellyfin. Program DATA, not Program Files. The existing install detection is a registry key, IIRC. It's possible the reg key was removed, but your existing data is still in C:\ProgramData\Jellyfin.

[jw2k_fr]

Your database should be located in C:\ProgramData\Jellyfin.  Program DATA, not Program Files.  The existing install detection is a registry key, IIRC.  It's possible the reg key was removed, but your existing data is still in C:\ProgramData\Jellyfin.

Yes!! it is indeed still there - ~35k files and ~3GB of data

Am I safe to just make a copy of the folder and then go ahead and try the (basic install) upgrade, or would it be better to try and reinstate the registry key first so that the installer takes that folder into account (rather than copying the old one back over the one created by 10.8.11)?

[jw2k_fr]

Having read https://github.com/jellyfin/jellyfin-ser.../README.md

In location: HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Jellyfin\Server

The following are all missing:

Name Type Data
DataFolder REG_EXPAND_SZ C:\ProgramData\Jellyfin\Server
InstallFolder REG_EXPAND_SZ C:\Program Files\Jellyfin\Server
ServiceAccountType REG_SZ None

What is likely to be my best course of action?

[TheDreadPirate]

Backup C:\ProgramData\Jellyfin. Uninstall if there is an uninstall entry. Reinstall Jellyfin as a basic install. Copy your backup folder back to C:\ProgramData\Jellyfin

[jw2k_fr]

Backup C:\ProgramData\Jellyfin.  Uninstall if there is an uninstall entry.  Reinstall Jellyfin as a basic install.  Copy your backup folder back to C:\ProgramData\Jellyfin

I copied C:\ProgramData\Jellyfin to the desktop and renamed the original to C:\ProgramData\JellyfinOld

There was no uninstall option in Add/Remove Programs, so I did a new, advanced install and selected the Server option and chose to use the default service (not the local account).

After the install completed I stopped the jellyfin server service, and...
 renamed      C:\ProgramData\Jellyfin     to     C:\ProgramDataJellyfinNew
 and also      C:\ProgramDataJellyfinOld     to     C:\ProgramDataJellyfin
 hence 'backing up' the new data and moving the old folder into its place.

I restarted the Jellyfin service but didn't see a System Tray icon. If I tried my old URL to manage the server I just saw a jellyfin logo and text, which I later found out is consistent with the service not running.

So, I rebooted and immediately saw a system tray icon, however I got an error message saying 
  "When running Jellyfin as a service, the tray application must be run as Administrator".  
  So I created a local account named jellyfin, set it to not be able to change its own password and set the option for the password to never expire.  I went back to services.msc and configured the Jellyfin Server service to use that account and tried restarting the service.  It started up and stayed that way this time with no error message.  Right-clicking on the system tray icon also showed the Jellyfin server running and when I opened the web admin page my original catalog of media also showed up in Jellyfin!!!

So, thank you for your assistance!  I'm very grateful to be able to watch something this evening.  Hopefully the old/existing data structure won't clash with any of the significant changes made in the last two releases!

I will report back here if I find any weirdnesses