Open System Preferences - iCloud : Click Sign Out
Disconnect from the network then Restart
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Copy the Serial Number and check it on
http://www.everymac.com/ultimate-mac-lookup/
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Open the
https://checkcoverage.apple.com site and paste your Serial Number into the box
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Quit Safari
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Clover Configurator is now able to generate SmUUID numbers for you :
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Quit Clover Configurator.
Restart
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If the two copies are the same you may
reconnect to the network and proceed to set up iMessage.