Hello, Unfortunately, it is not possible to activate Windows 10 Pro using a Windows 11 Pro license. Each version of Windows requires its own unique license key for activation. If you have a Windows 11 Pro license, it can only be used to activate Windows 11 Pro. If you need to activate Windows 10 Pro, you will need to obtain a separate license key for that version. I hope this helps! Best Regards, Hania Lian
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