dadajensen wrote:I don't have the Temporary location like you? (I'm using DSM 4.1)
How can that be?
That's why I was asking - to confirm that the system properly detects your single hdd (I have two volumes from two hdd's and can choose where to put the temp files).
I haven't experienced your problem myself, ext4 supports files over 4Gb. At this point can only suggest a full hdd wipe and OS reinstall.