Yes, it is the 3rd party ones that appear on my "Transitions" tab. They start with "blown apart, bouncing cubes, ..." and end with "..., Wave, Zoom". I had all these transitions on my previous computer. I can not remember if I had to do something special to activate those 3rd party items.

Do you have any ideas how to get the "Render As" : Image Sequence back (which I had before)?

Yes, it is the 3rd party ones that appear on my "Transitions" tab. They start with "blown apart, bouncing cubes, ..." and end with "..., Wave, Zoom".

They are NewBlueFX transitions. As you've got a new computer, you will no doubt need to register/activate that NBFX package again. To do so, place an NBFX transition over two video events on Vegas Pro's timeline, click on the transition icon and then click on 'About' to get to NBFX's application manager where you can register/activate that NBFX package. Of course, you will need the serial number for NBFX's transition package which you should already have or be obtainable from your NewBlueFX My Account.

Otherwise, you will probably need to contact NewBlueFX Support about the problem.

Re the Render options, try resetting Vegas Pro back to its default (factory) settings following exactly the procedure outlined here.

1) I can no longer render as "image sequence" and I would love to be able to do that again.

On this point, I think you run into the same problem as this thread: https://www.vegascreativesoftware.info/us/forum/image-sequence-render-option-gone--142150/

This bug was fixed in VP 19: https://www.vegascreativesoftware.info/us/forum/vegas-pro-vegas-post-release-history--104998/#ca838951

• Fix issue where Image Sequence does not appear in the format list in the Render As dialog

And for 18, there doesn't seem to be a direct fix.