Since yesterday I see the error attached as image.

Translation:

"Connection with Communication Service was broken and cannot be restored! GOG Galaxy will be closed."

The client works only in Offline Mode, but after logging in, it crashes after few seconds.

First step always - Google for the error.

https://www.google.pl/search?q=Connection+with+Communication+Service+was+broken+and+cannot+be+restored!+GOG+Galaxy+will+be+closed

You should be doing that on any error you received for any program. Yes, google exists for more than looking up pictures of Alexandra Nice. :)

The error comes from a number of reasons and different solutions exist.

For some folks, security programs get in the way:

https://www.gog.com/forum/general/connection_to_gog_galaxy_communication_service_was_lost

For others, Galaxy can't get past your computer's firewall and that needs to be checked.

I would start there as well as scanning the previous threads on the topic to see if anything looks good.

Please let us know how things work out.

Try running GalaxyCommunication.exe manually and see if that helps.
Hold win key, press R and in the Run window type:
%ALLUSERSPROFILE%\GOG.com\Galaxy\redist\
and confirm with enter. Find the application mentioned above and double click ; )

Otherwise try reinstalling Galaxy and if the problem still occurs, give as a bit more informations. Like version of the Galaxy client, operating system. And please report the issue at mantis
Don't forget to include your Galaxy logs: %ALLUSERSPROFILE%\GOG.com\Galaxy\logs
We may want to have a peek at them ; p

I see error in logs:

"Failure getting the explorer.exe token"

I think the most possible fault could be the custom gui theme.

I'm going to try to restore factory default settings later and try again.
I will update this thread when I would know more.



Edit: Factory files restored and problem is solved.