It gets about 75% done, and then it spits out an error saying cannot copy files to the volume. At one point, everything worked fine. So far, I've tried: 1) Erasing the external HD (quick format, zero out) 2) Another External HD 3) Repairing Permissions on computer 4) Other system maintenance I ran a terminal command to view the Time Machine log and it looks like it stops when it tries to backup my VMware Windows Partition. Tonight I will exclude the single partition file from my backup and see if that helps. Is Time Machine not compatible with VMWare software?