Why does my Mac Mini (2012) lock up with a fresh Mavericks install? I've reinstalled OS X Mavericks from scratch twice on my (usually headless) Mac Mini, but it keeps locking up after ten or fifteen minutes of use - even just Safari browsing. I use Screen Sharing with the firewall off (for now - to rule that out as a cause of the problem).

I connected an HDTV to see what was going on when the Mini locked up and I saw this:



...which doesn't look good.

I've run a full 'memtest' in single-user mode, twice, and that says it's OK. I'll try AHT when I get the chance, but does anyone have any advice or suggestions as to the cause?
I eventually found that the problem was caused by not-quite-firmly-seated RAM.