Are you running into this error, and then TabCmd stops?
handshake alert: unrecognized_name
It used to work just fine, you say? The only thing you did was upgrade server?
Then I bet you didn’t update your client-side TabCmd installer. You need to.
Uninstall what you have on the client and re-install the version meant to be used with 8.1 from C:Program FilesTableauTableau Server8.1extras