GOG Galaxy 2.0 is unable to find the game Return to Castle Wolfenstein. It does not show up in my "Owned games" and "Installed" tabs and manually adding it by scanning the game folder does also nothing. Please fix this.

shows up fine for me. its sorted under "w"

I have a similar problem with another game (Alan Wake's American Nightmare) for exactly two months, but there is still no any reaction from GOG.

I'm not an expert, but it seems to me that something is wrong with the database from which GOG Galaxy 2.0 imports the information about the games you own. I have a reason to think so because I did a fresh install of GOG Galaxy 2.0 on my laptop, where Galaxy had never been installed before, and got exactly the same result - the game is still missing from my library. It definitely doesn't look like a problem on the user side.

You can try to create a report on Mantis, but don't put too much hope in it. There are hundreds of reports on Mantis (including mine) and only 16 of them have been resolved. (:

The game is present in my library, it's just - as Bustacap already mentioned - wrongly sorted under "W" instead of "R".

You didn't read the first post carefully, did you?

It doesn't matter how it's sorted - under "R" or under "W" - when it doesn't appear in the library at all, even if you try to import it manually. (:

Missing games is a well-known issue faced by many GOG Galaxy 2.0 users. I suggest you take a closer look at your library. There is a chance that some game(s) may be missing.

The latest GOG Galaxy update from yesterday fixed the problem. RtCW is now showing up in both lists but still not in alphabetical order (game name starts with R not W).

You can override the order by editing the game and changing the Sorting Title. I think the logic is to have all the Wolfenstein games listed together under W hence why it defaults this way

Yeah I totally get that logic to have all Wolf games right next to each other but I rather have them sorted the same way it is when I go through my library using the web version. Your tip with changing the "Sorting Title" did the trick easily. Thanks for pointing me into the right direction.

Mantis is a bug tracker, not a support center.

You should contact the support directly by submitting a ticket here:
https://support.gog.com/hc/en-us/requests/new?form=account&product=galaxy
Select problem type - 'game not visible on shelf/list'

An official support ticket is required for GOG staff to access your account details.

The game is missing from GOG Galaxy, not from my library on the site.

This support form is for a library on a site, where I don't have any problems.