I have 2 seperate Steam folders, how do I combine them?

[Janii]

Hey, I have a Steam folder in my (D:) Drive and a SteamLibrary folder in my (D:) Drive. Now the thing is, I have some games installed in my Steam/steamapps/common folder and some games are in my SteamLibrary/steamapps/common folder. My games keep uninstalling themselves because Steam doesn't know if they're there or not. Can someone tell me how I can combine them so all games are in one folder instead of two seperate ones?

[ReBoot]

Moe the games from the SteamLibrary folder into the Steam folder and start installing there. Steam should discover the existing files.

[Janii]

That is all? Oh well :D Thank you!

[ReBoot]

That, or fix the ordeal with games getting uninstalled. That's not normal behaviour, that's caused by a technical issue (I had this with a kernel panic with a game running, said game got "uninstalled"). Although keeping the games safe & sound inside the Steam folder is one way to fix it.

[Janii]

And how do I fix this?

[ReBoot]

Well, find the culprit. The reason is SOMETHING interfering with Steam's bookkeeping.
The most likely cause is crapware like (but not only) CCleaner. Those braindead programs are supposed to "clean", that is remove unneeded files therefor "tuning" the system, but guess what, Steam's bookkeeping is very much needed. Software running in background needlessly locking files can cause this as well.
The next likely cause are system crashes. Files getting damaged when the file system driver gets killed off is pretty much the norm.
https://support.steampowered.com/kb_article.php?ref=8379-RYIP-2998