How to fix a macOS App Store ‘Cannot Update App’ error

If you see an error like “GarageBand cannot be updated because it was refunded or purchased with a different Apple ID,” it may surprise you. Isn’t GarageBand free? Isn’t your Apple ID the one in use on your Mac?Apple cryptographically encodes into every app downloaded the Apple ID of the purchaser. That’s true with “free” apps (truly free or free with in-app purchases) and paid ones alike, including Apple’s own software, such as Pages and GarageBa