Time Machine keeps asking to create new backup?

Every time a backup completes I get this message -

'Time Machine completed a verification of your backups. To improve reliability, Time Machine must create a new backup for you.'

I am backing up to Lacie Network Space 2 drive via wifi.

Does anybody know how to correct this?

Solution 1:

There is a very good thread here

https://discussions.apple.com/thread/3658856?start=45&tstart=0

On page 4, user Hoppah discovers that his Time Machine (TM) backups go corrupt if they occur simultaneously with "RAID scrubbing." The RAID scrubbing is a function of the network application server (NAS) run periodically to check consistency.

Hoopah used the TimeMachineEditor utility to ensure that TM backups did not occur at the same time as the RAID scrubbing. That solved his problem.

There is a post from a user Christof Birkenmaier, also on page 4, about how to mount the disk image of the backup and delete the portion of the backup causing the problem. It is a very ugly fix that requires editing the TM record of its state. Scary.

A blog entry at

http://blog.jthon.com/?p=31

explains loading the TM disk image with the Disk Utility to repair it. If that fails, it explains a command line method to run a file system check on the attached, but not mounted TM disk image.

Elsewhere in the thread first referenced above, from discussions.apple.com, on page 3, there is information about how to look at log files to spot the errors.

It appears TM backups may be corrupted if the network connection is interrupted during backup. You pack up and leave your house while the backup is running. That pulls the plug on your wireless connection to the backup device. Nasty thing to do to TM.

I have decided to run TM manually, when I know it won't get interrupted, and when I know the NAS is not doing RAID scrubbing.

Solution 2:

This will not get fixed until Time Machine re-engineer its approach and move away from using a remote-mounted disk image over the network.

The problem lies due to network connections inherently being unreliable (more so wireless networks). However the file system (HFS+) was built for locally-attached disk and assumes that the connection is mostly reliable. Using Time Machine over the network is like writing to a hard drive in which you often unplug the cable mid-transfer. Eventually corruptions occur.

The only way to correct this is to file a bug report to increase the priority of fixing this within Apple's engineering group.

More information here.