Time Capsule - Failed to mount disk image

LeonGarfield used Ask the Experts™
OS X 10.6.8

I have 2 Apple computers that are backing up to one Time Capsule using Time Machine. Currently the backup is not working on both computers. The message says that it can't mount the disk image. I tried using the Disk Utility to run a repair but it says that it can't fix it.

I found the following post that should solve my problem but I need step-by-step instructions.

In that post there is a reference to http://blog.jthon.com/?p=31 in which it talks about running HDIUTIL and FSCK_HFS. I need step-by-step help to run these commands.
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Before you get into command line tools .. have you tried??

1. Connect the TimeCapsule to one of your Macs via Ethernet cable and do not run diagnostics over WiFi.

2. Disabling Time Machine -  go into the Time Machine System Preferences, TURN IT OFF on both Macs

3. If you can open the TimeCapsule drive in the Finder but when you double click and try and mount  the specific sparseimage for the individual computer Time Machine backups .. it fails .. then you have a few choices.
  a. Try re-enabling Time Machine, reselect the TimeCapsule and it will try and restart a backup and it might resolve the issue
  b. Drag the sparsebundle to the Disk Utility sidebar, Select the sparsebundle, then click Repair, If the repair is successful, attempt to backup via Time Machine.
  c. You could try the more hardcore hdiutil tools - details here .. http://www.iotashan.com/2009/01/fixing-corrupt-time-machine-sparsebundles/
  d. Delete the sparsebundle backup and then re-enable the TimeMachine and reselect the TimeCapsule and it will create a brand new backup (you'll have lost the historic backups)
There is an excellent and very comprehensive Time Machine troubleshooting guide here:



Correction to my question.

One computer is NOT having a problem backing up to the Time Capsule.

Does this change the step you gave?

1. The Time Capsule is always connected to Ethernet and so is the computer that is having the problem.

2. Disabling Time Machine -  Do I still need to turn off Time Machine on both computers since one of them it working?

3. If you can open the Time Capsule drive in the Finder - On the computer that is having the problem, in Finder, under Devices, there is no Time Capsule listed. On the computer that is working, in Finder, under Devices, the Time Capsule appears during the backup.

In system preferences for Time Machine, when Time Machine is trying to start a backup, it says "Making backup disk available".  

Sometimes when Time Machine gives up a window pops up and says:
Time Machine could not complete the backup. The backup disk image "/Volumes/Data/users iMac.sparsebundle" could not be accessed (error 109)
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1. Good
2. No need to disable TimeMachine on working Mac (for now)
3. The fact that the TimeMachine is not appearing on the problem Mac ... or is giving the error (could not be accessed...) would indicate a problem with the connection

There are a few things you need to check .. as per the link above
hardware: is the Ethernet cable intact - any possible damage or wear on the cable?
network: is there any reason why the mac would lose or drop connection to the timecapsule?
software: use the working mac to open the timecapsule, view the sparsebundle file for the iMac that has problems and run it through the Repair Disk function in Disk Utility


On the website you gave it listed "Try repairing them, per item A5". According to this page http://pondini.org/TM/A5b.html the picture shows that in Finder, the Time Capsule should be listed under SHARED. In my comments above I was talking about the Devices list. My mistake.

-I found the sparsebundles and ran a repair-
1) I was successful connecting to the Time Capsule, 1st I had to click "connect as".
2) I dragged the sparsebundle to the Disk Utility and Ran the Repair.
I got this message:
This utility can't repair this disk. Backup as many files...and format the disk.

What next.
Did you try and repair the sparsebundle?  Not the timecapsule itself?  You need to make sure it is the sparsebundle file which is being repaired.


There were 2 sparsebundles listed. I dragged the sparsebundle for the computer that has the problem.
Can you try that same process with disk utility on the Mac which was failing to backup to timemachine .. in case it is permission-based errors which are preventing the repair.

Can you supply a screenshot of Disk Utility showing the application and error?


I already ran the Disk Utility using the computer with the problem.

So you want me to no run it on the computer that is working fine?
I wanted you to attach a screenshot of disk utility on the computer that is working so we can see clearly the image being selected and the error.
The next stage is to run the command line repair tools as I outlined in step C in the earlier post.


Last time I ran the Disk Utility it gave a lot of information. This time no message appears in the Disk Utility, all that appears is a popup window that says it can't  fix the problem and to backup your data.
Move onto the command line repair options step C ... unless you don't care about recovering the backup and are happy to start a new one in which case delete or rename the sparsebundle file that is not working and the iMac will create a new one when you restart Tiemmachine


How do I format the commands?

This is the Disk Image path /Volumes/Data/User's iMac (2).sparsebundle.
I got this from the Disk Utility.
Since there is a space in the path name, do I need to use quotes?
There's a nice trick in OSX .. if you just type the command but don't enter any of the path to the sparsebundle file.
Instead .. drop the sparsebundle file onto the Terminal window and OSX will write the full path and quote or mark the spaces correctly.

If it looks OK then simply press RETURN to execute the command
For those that prefer the keyboard over the mouse or touchpad, you can either put backslashes in front of the spaces and parethesis or just put quotes around the whole thing.  Quotes are simpler for typing in manually.  If you use command completion, the shell automatically puts backslashes if there aren't any name collisions.

/Volumes/Data/User's\ iMac\ \(2\).sparsebundle
"/Volumes/Data/User's iMac (2).sparsebundle"


I won't have access to the computer for 2 to 3 weeks. I will try it once I get back and post right away.


I finally was able to get to the mac and I ran the following with the results. The results are not like what is posted here http://blog.jthon.com/?p=31.  What next?

P.S. I modified on this post the name of the sparsebundle to keep the user anonymous.

Last login: Thu Mar  6 10:42:00 on console
js-imac-2:~ js$
js-imac-2:~ js$ hdiutil attach -nomount -readwrite /Volumes/Data/Jac\ SSS\ iMac\ \(2\).sparsebundle
/dev/disk1                Apple_partition_scheme               
/dev/disk1s1              Apple_partition_map                  
/dev/disk1s2              Apple_HFSX                           
js-imac-2:~ js$ fsck_hfs -rf /dev/disk1s2
** /dev/rdisk1s2
   Executing fsck_hfs (version diskdev_cmds-491.6~3).
** Checking Journaled HFS Plus volume.
   Invalid B-tree node size
(3, 0)
** The volume   could not be verified completely.
js-imac-2:~ js$
It sounds like the disk directory is damaged beyond the ability of fsck to repair it.

Your only hope is Disk Warrior:  http://www.alsoft.com


that's it! I need to dump the backup and start from scratch?
Either that or try to fix the backup with Disk Warrior.


I will try Disk warrior.

If it doesn't work how do I remove the corrupted sparsebundle and start anew? remember I have 2 computers backing up to the TimeCapsule and only one sparsebundle has a problem.
Yes. You can simply remove the sparse bundle and start afresh. You will lose the ability to check for old erased or changed files, though, since your backup will be brand new.


1) how do I remove the sparse bundle?


2) If I hold onto the damaged sparcebundle, how do I tell timeMachine to leave the damaged one and start a new backup.
Time Capsule should show up under "shared" in the sidebar of any finder window. If it does not, click "show" beside "shared".  Also make sure you have "connected servers" checked in the sidebar tab of the Finder prefs.

Double click on Time Capsule in Finder, then on the Data Volume. It may take a few seconds, but eventually the sparsebundle should appear and you can just drag it to the trash, or alternatively copy it to another volume, then trash it.

Telling it to ignore the existing sparse bundle is a complicate issue. You might have a look here:



I was not able to fix the sparsebundle. It was time to throw in the towel. I had to delete it and start the backup from scratch.

Thank you for all your help.


I've requested that this question be closed as follows:

Accepted answer: 0 points for LeonGarfield's comment #a40134750

for the following reason:

I was not able to resolve the problem. The backup was too corrupted to be fixed. I had to delete all backups and start from scratch.
Leon was given very comprehensive and thorough answers on all the possible ways to try and repair the TimeMachine. It is not the fault of the experts that the device was unable to be repaired.

The answers and steps are still valid so points should be awarded.
The answers given did lead to a solution. The solution was to delete the sparsebundle that was damaged beyond repair and create a fresh one. That solution appears explicitly in the series of questions and answers beginning at ID 40047949 and ending at ID 40087140 and was implicit in the answers given by Eoin O'Sullivan.

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