OSX partition failed I stumbled upon errors when I tried to partition my HD for an ubuntu partition. First it kept saying Partition Failed: Filesystem Verification failed That problem did disappear after a while. Probably when I repaired permissions. Then it kept saying Could not unmount disk "HD"

I tried unmounting disk manually, though that brought up Filesystem verification failed again.
There is a solution to your problem:

Filesystem verification can be stopped by booting to single-user mode, and then typing in order:

/sbin/fsck -fy
reboot


Could not unmount disk is because you are probably using it. Try booting from Recovery HD. If problem persists, boot Recovery from USB or use Internet Recovery to partition disk.