Currently Being ModeratedJan 8, 2013 12:27 PM (in response to LAUSBUA)
Are you using wireless?
I would expect it to happen now and again with wireless.. as it is easy to corrupt something.
Next time it happens try to fix the sparsebundle. Use the method here.
If you want snapshots of the disk.. use superduper and plug it in via ethernet.. they will keep perfectly. The very nature of TM is to keep mashing up the existing backup.. one day it is going to shoot itself in the foot, especially on wireless and especially with the network issues Mountain Lion brings.