I've captured video with OBS and dropped it into VSE as I always do.
I've set 25% proxy and FreeRun TC for all movie strips and hit "Rebuild Proxy and TC indicies".
Blender starts the jobs nicely, but crashes at some point. No idea why that happens.
There's plenty of disk space left for the proxies to be saved.
Here's the Belnder's backtrace (crash file):
I'm running Linux Mint 18 KDE 5 64-bit.
Blender version is 2.78 (date: 2016-12-08) from blender buildbot IIRC.