Never had any issues before but bought a game and it is visible under order history and also in library but has not appeared under owned games. Don't seem to be able to install it from library. Anyone had this happen and now how to fix it? cheers

What do you mean: doesn't appear under "owned games"?
That it isn't marked in the store as "in library"? Offline installers or Galaxy?
If you see it in your library (offline installer), you should be able to download.

If you're trying to download it through Galaxy, then it's probably just another temporary Galaxy glitch of which that program apparently has so many...

Left side of screen, has tab "Owned games". It's 100% not in here. If I got to the game's page in the store it says that it is in my library. I have tried to install it from here but nothing happens. I don't seem to be able to install anything from the library screen and only from the Owned games tab...

1. While GOG Galaxy isn't running, move the following folder to the desktop:
C:\ProgramData\GOG.com\Galaxy\storage
2. When you next start it up, you should see "Importing - ##%" at the bottom.
3. Once that finishes, click the cogwheel in the top left, choose Add Games & Friends, then Scan Folders for GOG Games. Pick the parent folder where you have your GOG games installed in order to add them back to the Installed section.

If the problem persists at that point, then the issue is server-side and you'll have to open a support ticket. Tell the chatbot the issue is of type "other" twice to skip to that step.

It's all resolved, thanks. Had to log out, open GOG in browser, then use some refresh account links that support kindly sent me. Pretty impressed with support, clear easy to follow instructions for those of us with limited techical knowledge.
Thanks for all the help, hopefully it's a one off.

If anyone comes across this thread wondering what those links were:
https://www.gog.com/account/refresh
https://www.gog.com/user/refresh
Just open one at a time in a new tab. Let the page load fully before moving on to the second. There won't be a confirmation message or anything. Just check if the issue is resolved.

Brilliant! This just worked for me.
In my case, BG3 would never appear after I bought it.
I moved the folder, note, you need to kill the helper app in memory so no GoG apps are running.
when I restarted, it reassembled my Owned Games and I now see BG3.