Just posting this here in case anyone else encountered this error, couldn't find the fix when i searched originally so ill post the info i got from rebellion support.

Hi,

I recently reinstalled windows after upgrading my CPU, motherboard and video card, Steam and sins have been reinstalled on a separate O:/ Drive with the old and new windows installed on C:/.

The error which has appeared three times after reinstalling the game on steam is,
"The product appears to be validated but the machine SID doesn't match. Try deleting the file O and re-activating."

I restored several folders like My Documents, AppData in the users folder after I reinstalled windows, is there a file in there that i may have missed which I need to remove in order to play the game?

Thanks for any help

Hello,

You'll need to navigate to this directory: C:\ProgramData\Ironclad Games\Sins of a Solar Empire\License

Then delete the Rebellion.bin file located there.

If there is no Rebellion.bin try navigating here instead: C:\Users\Public\Documents\My Games\Ironclad Games\Sins of a Solar Empire Rebellion\License

Let me know if that resolves your problem or if you have any further questions.
--
Rebellion Support
[email protected]

Hopefully next time someone googles the problem this will come up, Thanks to stardock as well for the quick reply.