
While I was looking into various ways to restore an ESXi config backup I came across a bug.
If you read VMware’s documentation about how to restore an ESXi config backup (you can find that here) you will see that it is full of references saying the build numbers must match.
The bug is that you can restore an ESXi config backup even if the build numbers don’t match. Which according to the VMware documentation should not be possible.
Even though it is possible to restore an ESXi config backup when the build numbers don’t match, I do not recommend doing this as there has to be a reason why VMware says that the build numbers must match.
In my testing I was able to replicate the bug in ESXi 7 and ESXi 8. I even went all the way back to ESXi 6.7 which had some interesting findings. I didn’t fully test everything in ESXi 6.7 as general support has ended on that version.
Here are my findings and how to replicate the bug.
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