teph@steph-XPS-13-9343:~$ kdenlive
Icon theme "OxyElegantBase" not found.
Icon theme "Breathe" not found.
Icon theme "gnome" not found.
Icon theme "OxyElegantBase" not found.
Icon theme "Breathe" not found.
Icon theme "gnome" not found.
OpenGL vendor:  "Intel Open Source Technology Center"
OpenGL renderer:  "Mesa DRI Intel(R) HD Graphics 5500 (Broadwell GT2) "
OpenGL Threaded:  false
OpenGL ARG_SYNC:  true
OpenGL OpenGLES:  false
OpenGL vendor:  "Intel Open Source Technology Center"
OpenGL renderer:  "Mesa DRI Intel(R) HD Graphics 5500 (Broadwell GT2) "
OpenGL Threaded:  false
OpenGL ARG_SYNC:  true
OpenGL OpenGLES:  false
QXcbConnection: XCB error: 8 (BadMatch), sequence: 5149, resource id: 56623367, major code: 155 (Unknown), minor code: 11
QXcbConnection: XCB error: 8 (BadMatch), sequence: 24942, resource id: 56623503, major code: 130 (Unknown), minor code: 3
QXcbConnection: XCB error: 8 (BadMatch), sequence: 24964, resource id: 56623503, major code: 130 (Unknown), minor code: 3
QXcbConnection: XCB error: 8 (BadMatch), sequence: 24978, resource id: 56623503, major code: 130 (Unknown), minor code: 3

ERROR: Caught a segmentation fault while loading plugin file:
/usr/lib/x86_64-linux-gnu/gstreamer-1.0/libgstlibav.so

Please either:
- remove it and restart.
- run with --gst-disable-segtrap --gst-disable-registry-fork and debug.

(kdenlive:3583): GStreamer-WARNING **: 
Trying to join task 0x55ac6a654b90 from its thread would deadlock.
You cannot change the state of an element from its streaming
thread. Use g_idle_add() or post a GstMessage on the bus to
schedule the state change from the main thread.

QObject::connect: No such signal QObject::aboutToClose()
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = kdenlive path = /usr/bin pid = 3583
KCrash: Arguments: /usr/bin/kdenlive 
KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi from kdeinit
sock_file=/run/user/1000/kdeinit5__0
The X11 connection broke: I/O error (code 1)
XIO:  fatal IO error 88 (Socket-Vorgang an einem nicht-Socket) on X server ":0"
      after 36 requests (36 known processed) with 0 events remaining.
QSocketNotifier: Socket notifiers cannot be enabled or disabled from another thread

[1]+  Angehalten              kdenlive


already purged and newly installed. keeps happening...