If you have multiple listings for the same device under your Microsoft account, it is generally a good idea to remove the outdated entry, especially if it corresponds to a device that is no longer in use or has undergone significant hardware changes, like a motherboard replacement. Removing the old device listing should not affect your other devices or your Microsoft 365 license, as long as you are signed in with the same account on your active devices.
By removing the outdated device, you may also resolve issues related to device limits on your Microsoft 365 account, which can help restore full functionality to your Office apps on the current device. Just ensure that you are signed in to your Microsoft account on the device you wish to keep using.
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