I am also having similar Time Machine issue. It backs up for a month or two with no problem, then get the Rebuild message. Though it will rebuild and start over, I don't like losing the ability to go back to a previous time. I did find this site also
http://www.garth.org/archives/2011,08,2 ... rrors.html However I am getting what I think some kind of mounting or pathing issue with Terminal.
For using Time machine I had created a folder named "TIMEMACHINE" on my synology DS410j. The Mac had created the file "My Computer's Name.sparsebundle" which is what is expected in the Garth post. I have tried listing the path part of the command in quotes "" and also without. (It did mention somewhere in there to do that if the sparsebundle was created with a apostrophe s, mine had done that.) I have also tried to include the NAS name in the path. No matter what I try I get "hdiutil: attach failed - No such file or directory"
By what I read on that site it sounds like if I could get it to mount and do the file repair, it would fix the problem and though maybe a tad time consuming, whenever this issue occurs a fix is possible instead of tossing a backup and starting over.
Any help or ideas on this.. Thanks