Windows Upgrade Help and more

I’m trying to upgrade my Windows 10 PC to Windows 11, which it says is compatible. The upgrade itself goes through, but afterwards I get an activation error (0xC004C003). It says Windows isn’t activated, even though my Windows 10 was fully genuine and activated. I’ve tried the activation troubleshooter, but it just says it can’t activate right now. Has anyone else hit this and found a fix?

That error can pop up if the digital license doesn't properly carry over. First, double-check you're signed into the Microsoft account linked to your Windows 10 license. If you are, try this command as admin: open Command Prompt and run "slmgr /rearm" then restart. After that, go to Activation settings and try "Troubleshoot" again—it often kicks it through on the second attempt.

Same here. After running that command, did it find a license or give a different error?

Can confirm. You could also try using the Activation Troubleshooter again, but this time select the option that says "I changed hardware on this device recently."

I had the same problem. For me, it just took a few reboots and waiting a day for the activation servers to catch up before it finally sorted itself out. Let me know if that works.

Same here. This happened to me, too. I had to use the Activation Troubleshooter and select the "I changed hardware" option to link my license.

Yeah, I had the same problem. The troubleshooter worked for me, but only after I made sure my Microsoft account was linked to my digital license before starting the upgrade.

Glad I'm not alone. Same issue on my PC.

Can confirm. I had the same problem. I fixed it by just letting it sit for a day, and it activated on its own after a few reboots.

+1 Yeah, that worked for me too. A quick tip: sometimes running the activation troubleshooter again after a reboot can nudge it along.