I know many people have trouble with the Steam integration plugin, who crashes often. This is my case too.
After using Galaxy for a few weeks / months, it seems to me that there is a recurring pattern in those crashes: the plugin crashes in a few seconds or minutes after Galaxy is launched if Steam is launched too. It happens also when getting out of sleep mode.
When it happens, I close every Galaxy processes, including the Galaxy Communication Service (never saw ghost Python processes, so I don't have to close them). Relaunching Galaxy leads to the exact same result in a few seconds or minutes.
But if I close Steam and launch Galaxy again, it works perfectly. If I launch Steam a few minutes later, I see no problem, the integration plugin doesn't crash. I have a quite large Steam library, in case it matters (6k).
Is this behavior something already known by you fellow Gog users ? If not, it can be local to my config, but it could also be a clue for developers to fix the problem.

1 Steam works best if its running BEFORE Galaxy 2 tries to sync to it

2. if Steam has more than one account logged i.e, you and a mate | kid use the same system then that crashs Galaxy because Gog didn't allow for it [was not tested] but the fix is to open Steam UI, log out and back into the Gog synced account then open Galaxy and launch your game

these two points are from my testing which is only in English

That's interesting. It is quite the opposite of my personal experience. I mean, I have no problem in steam at all, never, but integration in Galaxy works way better if Steam is launched AFTER Galaxy.

For the record, I have an alternate Steam account but I almost never log in it on this computer. I did once or twice, so maybe there are cached files which can interfere ? This second account was never added to Galaxy.

By the way, thanks for your reply.

just to be clear, step 1 is at sync time i.e, when you first set up your Gog Galaxy to download and track Steam games... not when you just want to play a game that has already been synced

step 2 is because what Galaxy uses to talk to Steam is just a plug in and doesn't have the full options [like account sign in\ out] so if you have two or more Steam accounts then Galaxy will not sync unless the account it has matches what Steam loggs... the Steam UI loggs the last account to use the system by default so whenever your mates \ kids play on this computer it auto locks your Galaxy account out

again if you hit this block the fix is open Steam UI, log out and back in then close Steam UI [actually close it so its not running in the background] then open your Steam game from Galaxy

I can confirm this. My Steam client is set to launch with the system startup and I never had any issues with the Steam integration crashing.

For me it crashes only when there is a new version of the Steam integration plugin available and Galaxy tries to update it.
I have to exit Galaxy completely and manually delete the Steam plugin folder from %localappdata%\GOG.com\Galaxy\plugins\installed and the plugin file from %programdata%\GOG.com\Galaxy\storage\plugins\ . Then after relaunching Galaxy and reconnecting to Steam the plugin gets updated and everything works fine.