FullSync

Two Way Sync between two hard drives -> not enough space on one hard disk
-> FullSync shows an error message, but creates new files with a size of 0
KB. After freeing some disk space and rerunning FullSync all the 0KB files
were synchronized, because the files were newer than the other files, the
real files were overwritten with the 0KB files. So most of my files were
destroyed.