Yep, I know there are other posts on this here, as well as elsewhere on the net. I believe I've read pretty much every one, and tried just about every suggestion. This seemed to happen after a clean removal and reinstall of the Radeon video drivers to address an unrelated problem. Might just be a coincidence. Win10 64 i7 4590K setup here btw.

Here are some things I have tried:

Launching with ctrl-shift to reset and clear cache

Tried Windows compatibility mode and troubleshooter

Removed and reinstalled Vegas 15 361 (also tried newest version)

Removed and reinstalled Radeon driver using DDU

Renaming Newblue folders as suggested in one post

Did clean uninstall of 361 as detailed here

Have removed nearly every video plugin from Window.

Vegas still hangs at the same point. If anyone has a different suggestion, I'd be grateful.

Update:

I finally removed every single third party video plugin, and got as far as "initializing gpu acceleration". Woo hoo!

I then disabled the Intel GPU, and Vegas finally loaded. Just thought I would add this in case someone else happens across the same issue. I've encountered this particular issue with the Intel adapter in the past. Usually reinstalling it will return QSV support.

Yay!