Unable to create image buffer error - please help

While editing I keep getting an error saying "unable to create image buffer" shortly followed by the program freezing or crashing.

I'm editing .mov files imported via the media browser shot on a Canon t5. I faced the same problem when editing MXF files from a Canon XF100 a few weeks ago.

I've been trying to solve this problem for weeks to no avail. The only workaround I have is to edit quickly in sessions and save frequently before the program freezes again.