You cannot join a HomeGroup with an error message "Windows cannot set up a HomeGroup on this computer. Error code: 0x80630801".
In addition, you may observe the issue that "Peer Networking Grouping" service cannot be started on this computer.
The error code 0x80630801 means PEER_E_CERT_STORE_CORRUPTED. The Identity Store has been corrupted.
To resolve this issue, we need to delete idstore.sst from the %appdata%\peernetworking folder. Please follow the steps below:
1. From an elevated CMD prompt, type in the following command:
Net stop p2pimsvc /y
2. Delete the following file:
3. Reboot the computer.
Then you should be able to join HomeGroup.