Since reinstalling windows recently I decided to give Vegas 8.1 another try.

When I plug in my serial number (from 8.0c) it tells me it should start with another number beginning with a G instead of an F. Anyone know a workaround to this issue?

I've installed it successfully in the past, so I don't know what's happening.

I just installed Vegas Pro 8.1 on a new machine with no other version installed and I used the same key I used with Vegas Pro 8.0. The same key should work. My first digit is a "1" (one), though - "F" is the second.

I know Edward, I have installed 8.1 several times without issue..I don't understand it. And yes, I meant the second digit not the first.

Sounds like a call to Customer Service may be in order.

Yes, you are right, that seems to be all there is to do at this point.

Uninstalled and reinstalled and serial number worked fine.

Unfortunately I still have black frames issue.

Extremely disappointing.

I had this issue too and uninstall/reinstall didnt help, I wrote to Sony Support and got a new working serial within a few hours. (On a saturday actually, was very happy and surprised.)

I need to add that my previous mentioned about still having black frames was not true and I was mistaken.

I previously had issue (on previous machine) where clips appeared blank on timeline, and would render black frames accordingly.

When attempting to use 8.1 on new machine recently everything (except external preview) was working fine, but when I rendered I saw occasional black in preview window. I didn't notice that those were only non-recompress events. Yes I felt pretty dumb when I figured that out.

Unfortunately, aside from lack of plug in support, I still have remaining issue:

When I click on the external preview button 8.1 freezes up on me, and has to be closed. Oh well.