Update: Mozy has released an update to fix this issue.
File this under the “why’s that happening” category… Â About a week ago, I noticed that my MacBook Pro’s Time Machine stopped working. Â It has been working flawlessly to an external drive hosted on my iMac at home, but I wanted something to back it up when I was on the road – for an upcoming trip where we’re likely to have lots of photos. Â (My friends lost a hard drive in their Mac while traveling across the country.)
Today, I found an article in ComputerWorld which links Mozy Backup to problems in Time Machine.  On further investigation, it is my problem.  As soon as I loaded Mozy on my MacBook Pro, the Time Machine problems began.  Unfortunately, I thought I had a corrupt spare image file on the backup volume, so I purged it and tried to start over.  Unfortunately, I was unable to start over and successfully backup my Mac using Time Machine.  After a couple tries, I did get it to work, only to find the next morning that it too had reported a problem with the disk image and had failed.  So, I’m down on my Time Machine, but for anyone else seeing these problems, thought the link above might be useful.
Here is an additional link: Â the Apple Support Forum discussion on the matter.