Windows Server 2022 does show me this warning.
System is valid and activated.
I installed it completely new on a spare hard drive, as the other installation went bonkers.
I'm unable to find my piece of paper so i tried it with this software. slmgr -dlvi shows me on the bonkers installation everythings fine.

Is there anything else i can supply to get the key?

i am running the software as administrator and HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion -> DigitalProductId is missing from the registry.

It is OEM_COA Channel or OEM:NONSLP channel but i definitely had a DVD with a license sticker

Hello, I was trying to backup my Windows 10 product key to be able to reinstall it if needed but I always get this error. I tried it with versions 1.5 and 1.4.2.

The character string cannot have zero length.
Parameter name: oldValue