@ paulinkibando

Welcome to the Blackmagic frustration club!
First off, I do not have the Ultrastudio, but I can only assume it needs to be set up properly, like most other BMD products, in the BlackMagic Control Panel in order to work the way we expect in vMix.
That means, resolutions and framerates have to match across the board.
When troubleshooting, it is best to insure that the product is working in Blackmagic Media Express, if it doesn't work there, it's a Blackmagic issue and you are most likely to get support from them.
If all is well there, then it should just be a matter of configuring things appropriately across all links in the chain, and hopefully you are good to go.
(I find setting things up with BMD products somewhat counter intuitive because you have to open up the Blackmagic Control Panel which is not the easiest thing to find when you don't know where it is)


Ice

@ paulinkibando

Again, I am not familiar with the Ultrastudio BUT, a black screen in vMix indicates to me that there is a mis-match in the settings somewhere, either from the camera to the Ultrastudio, or the Ultrastudio to vMix.
The fact that it is not showing up as an external output device indicates to me that it is not configured for output in it's current state, but there again, it could be a driver issue. Are the drivers up to date?
And, back to my earlier post, does it work in Blackmagic Media Express?
Are you running Windows 7, 8 or 10?
The more information you can provide, the better able someone will be at helping to resolve your issue.
As alluded to, Blackmagic products can be very frustrating to work with, not that they don't work, just that they are very particular with how they work. Very rarely are they "plug & play", they have to be configured properly to work properly.


Ice

@ paulinkibando

What are your settings in 'Blackmagic Control Panel'?
Or perhaps it's now the 'Blackmagic Desktop Video Utility' in Windows 10 in the Blackmagic folder.
(I just noticed this so I'm not sure if it's from a recent update or a download I made from Blackmagic or if it is as a result of upgrade to W10, I've never seen this "utility" before, but it performs the same function as the 'Control Panel' did).
If you can't get a signal IN or OUT of Blackmagic Media Express, you may need to contact Blackmagic support and possibly send your card back for testing.


Ice