Bizzare Time Machine message

[Cave Man]

I have all four of our laptop Macs backing up to a single 3 TB hard drive that is connected to the new 802.11ac Airport Extreme Base Station. The hard drive is partitioned into 4 volumes, one for each of the laptops. It has been working perfectly fine for the last several months, but today one of the computers, an i7 Sandy Bridge MacBook Pro, received this error message:

Time Machine completed a verification of your backups on “AirPort Extreme”. To improve reliability, Time Machine must create a new backup for you

Click Start New Backup to create a new backup. This will remove your existing backup history. This could take several hours.

Click Back Up Later to be reminded tomorrow. Time Machine won’t perform backups during this time.

I'm prompted with two buttons, one to erase the sparse image and start over with a new backup, and one to remind me later (dismiss). A strange feature is this sparse image is locked (pad-locked icon) but none of the other computers' sparse image icon is locked. I unlocked it with Get Info but that does not fix the problem. The sparse image does not show up in Disk Utility, even though I have opened it in a finder window.

None of the other 3 laptops are having this problem. All four are running 10.8.4 Mountain Lion. Any ideas how to get this fixed without redoing a backup?

 

[FreakinEurekan]

I've not found a way. I used to back up to a ReadyNAS and would get this every few months, ended up deleting & restarting the backup each time. I switched to USB backup about 9 mos ago and never got the message there. I put the newest Time Capsule in about 2 weeks ago, hopefully it'll be reliable too.

 

[ColdCase]

Can't help on the fix. If you are connected wirelessly, there is always a small chance that there was a connection glitch. How solid is the wireless signal to that Mac?

 

[Nermal]

I've had this message too, backing up to an older (4th gen?) AirPort. No idea what causes it or how to get around it though...

 

[priitv8]

That seems to be the case when one backs up to 3rd party NAS-es or AirPort USB-connected drive.
This validation and error message appeared together with Lion, if memory serves.
There's also lots of discussion on the net about it.
http://pondini.org/TM/C13.html
I've found one process description to attempt remedy, but TBH it has never worked for me:
http://www.garth.org/archives/2011,08,27,169,fix-time-machine-sparsebundle-nas-based-backup-errors.html
And I can tell, this has nothing to do with your laptops. It is a disk problem, because always when I get this and have checked the backup sparsebundle, there is some sort of low-level filesystem error causing it. As if the drive had been removed without unmounting properly.

 

[opinio]

As if the drive had been removed without unmounting properly.

I have had the same issue (as the OP) happen in the past as well. I have often wondered if it was an unmounting issue as well, but have also wondered if the unmounting comes from the fact that the APE or TC do not have any safe way to shut down. You cannot disconnect all users when you shut it down. So if it is powered down (unplugged) in mid-TM backup does this create the issue? I.E. the drive has been 'removed' without unmounting properly?

I cannot believe Apple took away the option to disconnect all users that used to be in the AirPort App. Now when you power down you just have to hope for the best.

 

[robpow]

I used to get these sort of messages when I first started using an external USB drive connected to an AirPort Extreme to back up two Macs. I then partitioned the disk in two and used one volume for each Mac and never had any issues again.

 

[maflynn]

I used to get this on my Qnap NAS often enough. When I switched to a drobo mini, things cleared up (so far it seems). I'm not sure why, other then something is getting corrupted in the backup

 

[priitv8]

So if it is powered down (unplugged) in mid-TM backup does this create the issue? I.E. the drive has been 'removed' without unmounting properly?

The thing is, all my network gear and external disks are powered via UPS-es. So I never power them down. I'm inclined towards USB device's sleep/disconnect or something similar causing this.
I think I have 4 options as for now:
1) switch to TC and eliminate USB from between AP and disk
2) change the USB enclosure/chipset (HDD itself is WD Red w IDLE timer turned off)
3) pursue robpow's hint with separate partitions (although I have 5 Macs to back up and I'm not sure if APX can cope with so many partitions on a disk)
4) check mic j's hint in this thread which suggests that one can backup to network volume also with classical folder structure, thus bypassing the additional sparsebundle complexity.

PS It's also worth noting, that backing up to a similar USB-HDD connected to a Mac Mini running OS X Server has never caused this problem!

 

[Cave Man]

Now a second MacBook Pro is having the same problem.

 

[priitv8]

Now a second MacBook Pro is having the same problem.

My experience is the same : these errors tend to appear in short succession for all machines I'm backing up.

 

[Cave Man]

My experience is the same : these errors tend to appear in short succession for all machines I'm backing up.

Did you get it resolved?

 

[priitv8]

Did you get it resolved?

Unfortunately not. I'm leaning towards getting a real TimeCapsule.
PS So far my workaround is this: I am keeping the bad copy as renamed file and start new backup.

 

[Lankyman]

Unfortunately not. I'm leaning towards getting a real TimeCapsule.
PS So far my workaround is this: I am keeping the bad copy as renamed file and start new backup.

Well I got a new vertical TimeCapsule 6 weeks ago and every setting is correct. However, my experience to date with said product hasn't entirely been a happy one. With my old USB external HD which I used for TM backups I used to get the following message occasionally -

Time Machine couldn't complete the back up to xxxxxxx. The backup disk is not available."

.

Since getting my new TC the above message is a regular occurrence. However, just 6 weeks in to my ownership of the TC I got the following message last night -

Time Machine completed a verification of your backups on “AirPort TimeCapsule”. To improve reliability, Time Machine must create a new backup for you

Click Start New Backup to create a new backup. This will remove your existing backup history. This could take several hours.

Click Back Up Later to be reminded tomorrow. Time Machine won’t perform backups during this time.

I lost 6 weeks worth of backups and had to start again. This has never happened to me before and I'm not best pleased. Reading past posts on here and other forums this appears to be a long standing issue which Apple cannot seem to resolve.

I'm running ML on a mid-2011 iMac with 16 gig of RAM. The machine is mostly put into sleep mode when I'm not using it. Anyone?