I recently purchased the VXDIAG SE device and ran into some issues — the Mercedes-Benz driver failed to install, and I couldn't update the firmware either. Frustrated, I reached out to VXDIAG support for help.

Here’s what they said:
“Do not install multiple diagnostic software programs on the same Windows system. Different vehicle brand software may conflict with one another, causing installation failures, errors, or the device not functioning properly.
The best practice is to install each brand’s software in a separate system partition.”

In short, if you're trying to use software for multiple brands on a single Windows installation, you're asking for trouble. The solution? Set up separate Windows partitions (or virtual machines) for each brand’s diagnostic software to avoid conflicts.
This advice saved me a lot of time — hope it helps someone else too!