Never had or seen this issue. Sounds like a hot key issue or stuck key? Make sure you are using the .deb version of Steam and not the Flatpak. Valve has said they don't support or maintain the flatpak version. Install .deb version and reboot your computer.

Steam is built on Chromium. Like the reason they discontinued support for Windows 7 was because Chromium stopped supporting Windows 7. Sounds like for some reason, your install of Steam got messed up and is trying to actually launch Chromium too.

Did you install Steam from the .deb pack or from the software center on Mint itself?

flatpak may not have updated yet, the 'system package' (apt version) has some fixes related to chrome/chromium/google api calls in the current release.

Edit: here's another topic where another had the same issue: https://test1.login.steam.hlxgame.cc/app/221410/discussions/0/688615792191736235/

yes, exact same thing has been happening to me. I'm actually relieved now because I only just made the connection that this probably had something to do with steam and not a virus. Like one of the people above said, I am using the flatpak version, so I'm going to try downloading the .deb and hopefully it stops.

I've been using the 'system package' version of steam from mint's software manager for years and have not (yet) experienced the chromium popups ... but it doesn't shock me that there are issues with the flatpak ... https://flathub.org/en/apps/com.valvesoftware.Steam

Note: This is a community package of Steam gaming plaform not officially supported by Valve.

Note: They misspelled 'platform' ... does not inspire confidence ...

I had that issue with the brave browser

Originally posted by HulaGirl86:

I had that issue with the brave browser

brave is chromium based, I can see that sharing hooks with chromium based steam, and I wouldn't get that popup issue using firefox that is not chromium based.

Just had this issue, had signed out all my old sessions so I needed to relog on my laptop. Got greeted by the chromium windows, but it seems to be fine after a restart.

Has been happening to me as well for the last couple of days, after starting my pc, it's very annoying, I couldn't find any info on how to stop this happening

Just had the issue like 5 minutes ago on Login, tbh didn't even think it was Steam until I closed it due to an unrelated issue of multiple Steam Sessions showing up at once on my Bazzite taskbar, and suddenly the Chromium windows stopped spawning when I restarted steam it seems to have fixed the issue, so whatever is causing it is intermittent

Originally posted by M:

yes, exact same thing has been happening to me. I'm actually relieved now because I only just made the connection that this probably had something to do with steam and not a virus. Like one of the people above said, I am using the flatpak version, so I'm going to try downloading the .deb and hopefully it stops.

Okay, I am now using the .deb version and earlier today a chromium tab opened again when I started steam, except this time it only opened one window, and after I closed it, no more instances popped up. So, switching versions is not a perfect fix, but it is good enough for me. By the way, I did notice better performance in games, speciffically CS2 after making the switch.

Edit: It happened again, and it opened multiple windows. I dont even know anymore, lol.

https://test1.login.steam.hlxgame.cc/sharedfiles/filedetails/?id=3616618902
What the actual ♥♥♥♥?
4 Chrome tabs which are attached to Steam - and 3 more orphaned Chrome tabs.
Chrome wasn't installed on this rig for years.
Ubuntu 25.04 x64
non-Flatpak Steam Beta
Everything's fresh and untampered.

i had this today, i think it happened when i accidently launched steam twice (via gnome). closing steam then launched a 2nd instance that worked correctly.

Originally posted by xanhast:

i had this today, i think it happened when i accidently launched steam twice (via gnome). closing steam then launched a 2nd instance that worked correctly.

This shouldn't even be possible under normal circumstances. Steam will check if it is already running and refuse to start a second instance. Do you run Steam directly via executable (~/.steam/steam/$PLATFORM/steam) instead of the intended start script chain? (/usr/bin/steam => /usr/lib/steam/steam => /usr/lib/steam/bin_steam.sh (bootstrap) => ~/.steam/steam/steam.sh).

Originally posted by Útost Alronbem:

https://test1.login.steam.hlxgame.cc/sharedfiles/filedetails/?id=3616618902
What the actual ♥♥♥♥?
4 Chrome tabs which are attached to Steam - and 3 more orphaned Chrome tabs.
Chrome wasn't installed on this rig for years.
Ubuntu 25.04 x64
non-Flatpak Steam Beta
Everything's fresh and untampered.

Just out of curiosity, are you on the steam beta or stable client? Do you use a chromium based web browser like Brave that may be somehow getting hooked by the CEF steam is built on?