I keep getting glitches in my After Effects output, always in the top left hand corner. Usually it's a square shaped glitch (like in the attached picture), but not always the same size, and sometimes it's an oblong. Usually it contains some kind of offset video, but on a few rare occasions it's been black.

I've tried with the Lagarith and Canopus lossless codecs, both in MP mode. I've tried playback in WMP, PPro and AE.

I've got other things I'm going to try (other codecs, single-threaded renders, disk write speeds), but since the problem is sporadic it's going to take quite a few tests to nail down.

Has anyone got any suggestion on where I should focus my efforts?

The system is broken. The lawmakers, judges and politicians are bought off and corrupted beyond belief.

If they can get away with this they can get away with anything.

Now watch these arseholes continue the accelerated forseclosure of homes they have no legal title over and the pillaging of people's pensions and life savings with absolute impunity.