Your system information

• Steam client version (build number or date): Built: Mar 19 2018, at 12:02:23
• Distribution (e.g. Ubuntu): Debian Stretch and Debian Buster
• Opted into Steam client beta?: No
• Have you checked for system updates?: Yes

Full system infos: https://gist.github.com/Nidhoegger/9bc1fccc065a8d8fb0c1c57b2ebc8b4c

Please describe your issue in as much detail as possible:

When quitting steam (e.g. via Tray -> Quit, via System Shutdown or via Update Dialog (restart steam)) the X11 server locks completly. Only mouse is moveable. My suspicion is that you use X11 exclusive mode or start spamming the X11 server with commands (havent debugged it yet). Sometimes it will start working again after a couple of minutes, most of the time I need to switch to a VT and kill steam with SIGKILL.

What I expect: Steam will quit without blocking X11 completly.

Steps for reproducing this issue:

1. Have steam running
2. Press Quit
3. Profit