I just tried to launch GoG Galaxy and was told I needed to update first. I clicked update and then got an error saying that my game library failed to load. Now nothing works. Any suggestions?

I'm in the same boat. The same thing happened to me as well.

try reinstalling

While GOG Galaxy isn't running,
1. Into the File Explorer address bar, paste C:\ProgramData\GOG.com\Galaxy\storage\
2. Delete the galaxy-2.0.db file. If that isn't enough, delete the entire storage folder.

If you don't mind using an SQLite editor, you can use Skolia's solution instead and fix the existing database.

This worked for me, thanks!

They have fixed the problem !
Just download the newest Galaxy client from the link on the bottom right at the front-page , then install that.
That should fix the problem. at least it did so for me. I had *NOT* started messing with the installation myself and had not attempted any of the fix suggested as I did not want to risk screwing up anything.

Thank you to everyone in forum for their fix for the problem or for trying to fix it , Thank you all !!!!

Also thank you to GOG for a speedy fix of their huge screw-up !

Official GOG post here :
https://www.gog.com/forum/general_beta_gog_galaxy_2.0/the_failed_to_load_game_database_error/post134
and
https://www.gog.com/forum/general_beta_gog_galaxy_2.0/the_failed_to_load_game_database_error/post137

Thanks, Ice_Mage, that worked. Sucks having to reinstall all my games, but at least I didn't lose them all permanently.

You should be able to just click the cogwheel in the top left, and choose Add games & friends, then Scan folders for GOG games.

Alternatively, if you still have the deleted galaxy-2.0.db file or storage folder in your Recycle Bin,
1. Click the cogwheel and choose Settings.
2. If the lower left corner doesn't list at least version 2.0.49.1, close the settings window. Then click the cogwheel again and choose Check for updates.
3. After updating, exit GOG Galaxy.
4. Move the existing C:\ProgramData\GOG.com\Galaxy\storage\galaxy-2.0.db file or C:\ProgramData\GOG.com\Galaxy\storage\ folder somewhere like the desktop.
5. Restore the deleted galaxy-2.0.db file or storage folder from the Recycle Bin.