How to unlock a apple watch without the previous owner email address
You are referring to Activation Lock which can only be removed by the Apple ID owner its locked to. You need to contact the prior owner so they can remove it from their account following How to remove Activation Lock - Apple Support
You can't unlock the watch. Apple won't unlock the watch. We can't help you unlock the watch. If you have purchased a used Apple Watch, which is still locked to the previous user and you can't contact them to remove the watch from their account, you have wasted your money on a useless device.
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Locked apple watch
