I suspect the hexadecimal string looks like this:

{3F2504E0-4F89-11D3-9A0C-0305E82C3301}

That's called a GUID (Globally Unique ID).

Open the registry editor (regedit.exe), and drill down to HKLM\SOFTWARE\Classes\CLSID. You'll see hundreds of GUIDs listed. Find yours, then expand it's folder to explore!

Example:

{0000000B-0F56-11D2-9887-00A0C969725B}
Sony ExpressFX Time Stretch
C:\Program Files (x86)\Sony\Shared Plug-Ins\Audio\sfxpfx3_x64.dll

BTW-- GUIDs are assigned by the developer and are the same for everyone. If your registry is missing the entry, tell us the GUID and we can tell you what plug-in is missing... and the .dll file.

Thanks for the info.
Mystery string is 0be320e2-aea5-46ee-924b-eff7b24d57ad

I opened regedit and searched for that but came up empty handed.
This is possibly because sometime ago I followed Supports advice and cleaned all things Sony from the system including the registry.

That'd also explain why Vegas cannot find out the name of the plugin.

Bob.

edit: I found it. Shouldn't have ticked the "Match Whole Word" option in Regedit's Find.

Missing dll was Shiftup, used to correct field order. The dll was in the right place but wasn't registered. Ran the batch file to register and project opens with no problem.

Very nicely done! And you would have had a subtle rendering error otherwise.

I came up empty on that GUID. Perhaps this is a plug-in that I wouldn't have in a stock 9d install? Or, maybe I am wrong about this GUID being constant. No trace of "Shiftup" in my registry either.

"Perhaps this is a plug-in that I wouldn't have in a stock 9d install?"

No you wouldn't as its a third party plugin, free and very useful.
If you're interested its in a VERY interesting thread about field order. That thread also contains a simply brilliant tip on how to check field order without a CRT.

Bob.