I changed a setting, i don't know the exact one since I can't open the application and look, it's something to do with video playback. I was trying the different options to see if any one worked better than the others. After choosing 1 it started crashing on launch with the error message "Could not create the video preview window. There is something wrong with your Kdenlive install or your driver settings, please fix it." I tried unistalling and reinstalling but no luck.

I'm running kdenlive 0.9.6-5ubuntu1 on Xubuntu 14.04.

I've tried looking through the forums for the location of the config file but it's not in the locations I've found references to. Does anyone know where the config file would be on this setup or anyway to fix the problem?


Edit.....................
I was able to start the application from a file association. It had the same error but opened the main window without the video preview window. I was then able to change the setting back.

I bet it's the GPU acceleration which causes the crashes.

If you can't access the Settings due to the crashes: you can rename ~/.config/kdenliverc to set settings back to default, which will turn off GPU acceleration.

I have issues as well. I reported them here: https://bugs.kde.org/show_bug.cgi?id=355259

I don't think the problem is the same on the (very old) 0.9.6 and the recent 15.9.0 : the video backend has completely changed in between.
However it can be an OpenGL issue in both case, in 0.9 times this was flagged as experimental...