File names typically look like: abc123-def456-7890-ghij-klmnopqrst.pcpkey – a long GUID (Globally Unique Identifier) followed by the extension.
The unique feature of PCPKEY is . You cannot copy a PCPKEY file to a USB drive and use it on another PC. That makes it ideal for anti-theft and secure boot scenarios but problematic for backups. pcpkey file
Then you can safely clear the TPM.