Fixing Windows Activation Issue 0x803FA067
This error commonly appears when switching from Windows Home to Pro, or when trying to activate Windows again after a significant hardware change.
How to fix error 0x803FA067
Disconnect from the internet
Temporarily disable Wi-Fi or unplug the Ethernet cable.
Manually enter your product key
Go to:
Settings > System > Activation > Change product key
Enter the key you received and continue.
Reconnect to the internet
After the key is accepted, turn your connection back on and restart the PC.
Other helpful checks
Activated on another PC?
If your key is transferable, you may need to remove it from the previous device before using it on a new one. Make sure it’s only in use on one device at a time.
Reactivating after a hardware change?
You can try reactivation through your Microsoft account:
Settings > Activation > Troubleshoot > I changed hardware on this device recently