idle and the devil

[Tim Peters]

[Siegfried Gonzi, reports widespread file corruption after copy+paste,
 under both IDLE and Emacs on Windows XP]

Try another machine.  I've never heard of this before, and that it occurs
under two programs for you says "machine-specific failure mode" to me.
Maybe a flaky memory chip, maybe a bad spot on a disk, maybe a driver
conflict, maybe a background program going insane, can't say.  But when you
see problems nobody else sees, nobody else sees them <0.9 wink>.