On the TMFDE window, in the Encryption Status tab, the Actions Status is "Unable to access disk" after installing TMFDE with SED (Self-encrypting drive) on a UEFI environment.
You may also check the encryption of the disk on the Encryption Status tab then selecting the disk name from the dropdown list.
On the Event Viewer page, in Event Viewer (Local) > EhStorTCGdrv, a similar error appears:
A TCG Command has return an error
To resolve the issue, go to Intel® Rapid Storage Technology (Intel® RST) and download the latest build of Intel Rapid Storage Technology.