Did GOG ever explain anything about this? I've never heard of GOG just arbitrarily deleting games from people's accounts before.

This is a first for me. I am as surprised as you are.

Edit: I have heard of GOG removing demos from their collection, but not directly from people's libraries.

It's one thing for GOG to remove the "sale" page, as they've done that before. But they've never just deleted stuff from people's account for no reason. This is not good.

I can still see it in my owned games on GALAXY but the install button is greyed out, unhappy :(
Guess it's time to buy a new hdd ...

Me too. In Galaxy, it's there, but install button greyed out. But when using browser to access my library, game demo is not even there! Vanished!

Hoping it's a glitch of sorts. I've been kind of lazy lately about backing up my installers, but mostly because I believed my library to be a secure and safe place for my purchased games and game demos (and game freebies too!). Now, it's possible GOG has a valid or legal reason for removing said game demo from my library, but I would have appreciated a notification or a warning or a statement explaining why. Also, since when is silently removing items from one's game shelf become a thing?

Here are a few related links:
https://twitter.com/timberborn
https://steamcommunity.com/app/1062090/eventcomments/3039354010645641451/

I loathe this behavior of removing games from our account libraries.

Missing the demo here too, and I still got my gog-manifest.dat and purchase receipts (from both email and the orders page) proving I had it at some point. People may want to get in touch with the supported about this issue.

Also always worth to mention: always keep a back up copy of your DRM free contents and their purchase/activation receipts.

Little edit: I just noticed my games count went down by one, again. So with Timberborn Demo, that's 2 missing now.

I had the demo in my account also, and now it is gone.

I have two redeem codes for it.
Inputting one code and the page displays:
"You already own this product. It won't be added to your game library."

Probably at the same time they partnered with Epic and allowed games with aspects of DRM to be sold here. Roughly when a blue announced something along those lines: "We allow developers now to create their content as they see fit, in order for them to distribute it through our expanding store". cannot remember thread name. It was meant as a reply to some of the voiced concerns for DRMed games finding their way here, i think... Gog started doing many weird things, nobody should ever feel safe for their library, anymore.

Besides, people warn that new installers have incorporated Galaxy elements that cause various inconveniences, telemetry etc. Older threads here with very old users, adviced people to back up installers as soon as you bought them, at that very instant at that. Well, that was the best piece of advice somebody could ever give. I myself was too relaxed and trusting on Gog, so i naturally neglected that. Couldn't foresee they would slowly rot away and become the exact opposite of what they once stood for. My nick was for joke or trolling purposes, back when i created this account; today, it unfortunately fully represents my sentiments exactly, alas.

Thanks for the links! Although they won't bring back the missing demo, at least they let me know what really happened.

Okay that's quite worrying what if the dev forces your hand to remove full games.

If they force them, then it's gone. My ex lost music she bought in the Apple store. So it CAN happen.
But forcing is not as easy as it sounds, if the contracts are done right.
That's why we love our offline installers, right?

True when I buy games on here i always download the offline installers.

It was quite worrying, but at least now I know why my games counter is decreased. Thanks for the info anyway.