Problem:

I cannot open Tech2win software after entering from GM software of VXDIAG full brands in 2019.07 2TB HDD format.

OBD2TOOL solution:

For 2019.07 version vxdiag full HDD,  you should run Tech2win from Porsche software (system) instead of GM software.
Choose device as GM MDI2 but not VXDIAG.

Note: This is for 2019.07 HDD only.