I know it's a very old version of SVP, (Pro 10) but it works great and I moved to a new computer recently, but the audio plugins folders are empty. The video plugins are there, but no audio. I read somewhere it's a registry permissions issue. Is there a work around?
Try resetting VP Hold down the CTRL + SHIFT keys at the same time and click the executable file <.exe> or a shortcut to start VP. A pop-up option asks, "Do you want to reset all Vegas Pro preferences to default values?" and "Delete all Cached Application Data?" Yes/OK and this will restore VP to the Factory Default Settings.
If that does not fix it, uninstall VP with a third-party uninstaller which also cleans leftover garbage, then re-install. Revo Uninstall app (free or pro version) always works good for me.
In either case, back up and/or write down the layouts and customization settings to make it a little easier to restore