Hello. I have been out of GOG for a while and now that I returned, I saw that my collection went from 24 to 23, and the first Fallout is gone from my account. I got it from the free promo back in the day but it's gone now. The other two games are still there.
Is that normal?

My collection is still there, you should contact Gog support, maybe with a copy of the Fallout 1 purchase.

I just logged in to reinstall Fallout 1 and my copy is also gone. Tactics and Fallout 2 are still there.

Edit: I tried hiding a random game and then unhiding it which made Fallout 1 reappear!

Mine went walkabout for a bit aussi, try reloading your library now and see if its returned

Fixed? Seems it`s not, as I see empty space on my shelf, instead of Fallout1.

The same strange thing happened to me just now. I had just bought Deponia 1 - 3 and went to my library that now had 27 games in it. Downloaded Deponia 1, browsed some other games on GoG in the meantime, went to my library again once the download was finished to download Deponia 2, and had only 26 games there because Fallout had disappeared. Closed Firefox, opened it again, went to my GoG library, Fallout still gone.

I think to remember that I read something about the Fallout IP having a new owner (at least the old games), so can it be that Fallout 1, 2 and Tactics are being removed from GoG now?

EDIT: And now Fallout is back again. Weird.

No it's just a glitch. Fallout has disappeared from my shelf again as well, but GOG's working on it.

Here are the latest news on the topic:
http://www.gog.com/forum/general/games_missing_from_my_shelf/post33

Same, what's going on here. I've have Fallout 1 in library.

I can see Fallout1 is in my library, only when I change view to list.
https://www.gog.com/account/games/list

Just had a look at my library and also noticed the empty spot on the shelf. And sure enough it's Fallout. However, after a refresh it was back. Now it's gone again. Seems to fluctuate between here and "Over There". I'm sure Walternate has a hand in this...

I created a support ticked 2 days ago and got a reply reply this morning saying the issue was fixed but the Fallout games were still missing. I reopened the ticket.
I did try all suggested fixes but nothing has worked for me so far.
The trouble is in supports hands now.

If you haven't done so already, try an account refresh: https://secure.gog.com/account/refresh/

I have done that and just tried once more.
No luck :'(
I hope to get a second reply to my trouble ticket soon.

Same here, it is also missing from my account page. Tried refreshing account as well as hiding and unhiding some games but it is still missing. Gog really need to sort the account section out, nothing but problems since the website redesign.

Edit: Going from List View to Shelf View, and back to List View seemed to have sorted it out for now.

Edit 2: Nope gone again. Trying the Shelf View trick doesn't work anymore, it has disappeared from both views.