Just Purchased MECHWARRIOR 5: MERCENARIES (03.23.2023).
Downloaded all the content and saw that there is a Serial Key to play the game.
Clicked on Serial Key and got this message.......

MECHWARRIOR 5: MERCENARIES
Serial keys depleted

Now What?.. How do i get my serial key? HELP!!!! How do i contact GOG and ask for a serial key??
The only page i can find is the HELP page which DOES NOT HELP!!!! (with Serial Keys)

Thanks, ThunderBoyDavid

This may be related to the fact that back when Mechwarrior 5 launched here on GOG, it came with another game (The Surge) as a bonus. I installed my copy through Galaxy, and the only thing at all serial-related was the bonus game, which was distributed as a giveaway code, rather then being directly added to your library as other bonuses or combinations typically have been.

Have you tried just instlaling the game and running it, with or without Galaxy? The game starts for me whether I have Galaxy running or not, but if it is, there's a popup on the title screen with my username and an invite code (necessary for multiplayer). If Galaxy isn't running, then either that popup doesn't appear or it says offline - I don't remember exactly.

Might be a store issue, someone posted about it on the main board a few days back:
https://www.gog.com/forum/general/bought_games_from_gog_storefront_but_am_getting_serial_keys_depleted_errors_how_do_i_contact_gog/page1

Apparently the guy solved it by e-mailing gog support (support@gog.com)