[winswitch] Unable to start xpra - cannot open log file

[Nikolaus Rath]

Hello,

Xpra has been working fine for me for a while, but it suddenly fails with:

$ xpra start ssh:nivellen.lon.corp.google.com --start=xfce4-terminal
Warning: invalid option: 'shadow-fullscreen'
Warning: invalid option: 'shadow-fullscreen'
2018-01-18 11:08:08,205 Warning: the python netifaces package is missing
2018-01-18 11:08:08,258 Xpra gtk2 client version 2.2-r17607 64-bit
2018-01-18 11:08:08,258  running on Linux Debian rodete rodete
2018-01-18 11:08:08,258 Warning: failed to import opencv:
2018-01-18 11:08:08,258  No module named cv2
2018-01-18 11:08:08,259  webcam forwarding is disabled
Warning: invalid option: 'shadow-fullscreen'
2018-01-18 11:08:08,608 GStreamer version 1.12.1 for Python 2.7.13 64-bit
2018-01-18 11:08:08,697 No OpenGL_accelerate module loaded: No module named
OpenGL_accelerate
2018-01-18 11:08:08,812 OpenGL enabled with Mesa DRI Intel(R) HD Graphics
620 (Kabylake GT2)
2018-01-18 11:08:08,831  keyboard settings: rules=evdev, model=kinesis,
layout=niko-kinesis
2018-01-18 11:08:08,831  desktop size is 1920x1200 with 1 screen:
2018-01-18 11:08:08,831   :0.0 (508x318 mm - DPI: 96x95)
2018-01-18 11:08:08,832     monitor 1 (550x350 mm - DPI: 88x87)
Warning: invalid option: 'shadow-fullscreen'
Warning: invalid option: 'shadow-fullscreen'
Warning: invalid option: 'shadow-fullscreen'
Warning: invalid option: 'shadow-fullscreen'
2018-01-18 11:08:16,682 Warning: the python netifaces package is missing
Warning: cannot use the system proxy for 'start' subcommand,
 failed to connect to '/run/xpra/system':
 [Errno 111] Connection refused
Warning: invalid option: 'shadow-fullscreen'
xpra initialization error:
 cannot open log file '${HOME}/.xpra/S260873.log': [Errno 2] No such file
or directory: '${HOME}/.xpra/S260873.log'
Error: displayfd failed
 did not provide a display number using displayfd
xpra initialization error:
 failed to identify the new server display!
2018-01-18 11:08:41,253 Error: failed to receive anything, not an xpra
server?
2018-01-18 11:08:41,253   could also be the wrong protocol, username,
password or port
2018-01-18 11:08:41,254 Connection lost
2018-01-18 11:08:41,256 Error: printing disabled:
2018-01-18 11:08:41,256  No module named cups

Does anyone have an idea where to look for the root cause? It's not clear
to me which warnings and errors are relevant here...

I don't remember making any system changes that may have caused this.

Best,
-Nikolaus