El Capitan Finder shows 10 GB more disk space I'm running 10.11.2 on a MBP 15". Since a few weeks ago I am observing a strange phenomenon: all disks show roughly 10GB more free space than they really have.

E.g. I plug a USB drive in that has 32 GB. Finder shows me 42 GB.

Other example: Finder shows that I have 11GB free. I pull a 2 GB file to the Finder and get the message: not enough disk space.

What could be the reason?
I tried out the usual Apple voodoo things (PRAM reset etc), and one behaved strange: when I started the Macbook with pressed Shift-key (safe start), it took very, very long. Usually this takes like 5 minutes, this time it took more than 40 Minutes (huh!).

After that I just restarted again and everything was fine. So it looks like safe start fixed the problem