As far as the plausible reasons behind this issue are concerned, it might be attributed to NAS, SMB, or limited access to Time Machine. Along the same lines, issues with the sparsebundle file itself could also bring up the aforementioned error. So in this guide, we will be addressing all these concerns which in turn should help you fix the “Time Machine couldn‘t complete backup, Disk image already in use” error. Follow along.
Fix Time Machine couldn‘t complete backup: Disk image already in use
It is recommended that you try out each of the below-mentioned workarounds and then see which one spells out success for you. So with that in mind, let’s get started.
FIX 1: Kill SMB Process
One of the biggest reasons why you are getting this error is the fact that even after Time Machine has completed the backup, the SMB process continues to run on the NAS and uses the sparsebundle file. So when Time Machine tries to start a new backup session, it is unable to do so because the sparsebundle file from the previous session is still being used by that SMB process.
So you will have to kill this process in order to let the Time machine use this sparsebundle for the new session. Do so and then check if it fixes the “Time Machine couldn’t complete the backup to ABC.local: The backup disk image “XYZ.sparsebundle” is already in use” error.
FIX 2: Restart NAS
This is the easiest of all the fixes and requires just a restart of your network-attached storage. Likewise, you could also disconnect the NAS from the router for a few seconds and then connect it back again. This should also fix the error “Time Machine couldn’t complete the backup to ABC.local: The backup disk image “XYZ.sparsebundle” is already in use”. However, the relief will be temporary as the bug might re-appear within a few hours. So it’s just a quick short-term workaround.
FIX 3: Use SMB 2/3
It is recommended that you only use the Server Message Block protocols 2.0 and 3.0. If you are still using the default 1.0, then here’s how to make a switch to 2/3.
FIX 4: Add Time Machine to Full Disk Access
FIX 5: Manually Recreate SparseBundle File
If none of the aforementioned methods worked out in your favor, then you will have to manually re-create the SparseBundle file using Terminal. Here’s how it could be done. So these were the five different methods to fix the error: Time Machine couldn’t complete the backup to ABC.local, The backup disk image “XYZ.sparsebundle” is already in use. If you have any queries concerning the aforementioned steps, do let us know in the comments. We will get back to you with a solution at the earliest.