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David, Mac Support Specialist
Category: Mac
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Experience:  BSc H.Dip Apple Certified Professional
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Time Machine couldnt complete the backup - error shown Backup

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Time Machine couldn’t complete the backup - error shown Backup disk image "/Volumes/Time Capsule/Stuart Parker’s MacBook Pro.sparsebundle” is already in use.
Hi, my name is XXXXX XXXXX I will do whatever I possibly can to help answer your questions.

Do you have more than one Mac? Are there other Macs that use this Time Capsule, for connection or backup?


Customer: replied 3 years ago.

Yes there is another MacBook using the Time Capsule


This could be easily fixed, or may take a bot of detective work and troubleshooting.

First please shut down both MacBooks, then plug out the Time Capsule.

Leave the Time Capsule plugged out for at least a minute, and connect it again.

The LED on the Time Capsule should go green after a couple of minutes, then start up the MacBook that hasn't backed up.

Click the Time Machine icon on the menu bar, and click Backup Now.

Let me know how this goes.

Customer: replied 3 years ago.

Did as you suggested - now both Macs backup successfully. May thanks. Question? What caused this error and how do I avoid it in future?



hi Stuart,

I'm sorry to keep you waiting, I had network problems of my own.

You should keep your software up to date to help in preventing this kind of thing happening again, but in this case I don't think there is anything that you have done to cause it, or need to avoid doing in future.

The exact reason why this was happening might not be clear, but it looks like the other Mac may have been accessing the Time Machine volume of the first Mac. You should let Time Machine take care of the backups, and not try to access the backup volumes using a Finder window or other software. I'm not saying this was what happened, but it could have been.

The volume on the Time Capsule drive must be accessed by one computer at a time, and if there was a Finder window open showing the volume contents, then the other drive would have been locked from using it.

Just like data on a drive can be written incorrectly, or read incorrectly by the hardware sometimes, sometimes a bug can creep in. That's the main reason a backup is needed at all, and because it is not 100% fail safe.

Under the hood Time Capsules use a lot of combined technologies and can be tricky to troubleshoot because of this. We were lucky in this case that it was what I suspected, the volume locked by another Mac.

You don't need to worry about this again, just run Software Update regularly using the Apple menu - Software Update.

On the other hand if this repeats the same behavior, then we need to look at other software that could be accessing and therefore locking the volume from use by Time Machine.

Please feel free to ask me anything on this, and if you have further questions in future I would be very happy to help you with them.

Have a great day!

Yours sincerely,
David and 2 other Mac Specialists are ready to help you

I'm just following up with you to see how everything is going, or if you needed any more help on this issue.

Feel free to contact me on this or any other Mac related questions.

Kind regards,

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