Currently, most Elgato Gaming Capture devices will not work if you update Windows to the current insider preview build - 20H1. 

This Windows beta build saw wider release on Apr 10, 2019.

 

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Affected Software

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Elgato Gaming Capture devices won't work in the following software:

Game Capture
4K Capture Utility
OBS
Streamlabs OBS

 

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Affected Hardware

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The affected Elgato Gaming Capture devices that will not work are:

Elgato Game Capture HD
Elgato Game Capture HD60
Elgato Game Capture HD60 S
Elgato Game Capture HD60 Pro
Elgato Game Capture 4K60 Pro
Elgato Video Capture

 

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Unaffected Hardware

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The two Elgato Gaming Capture devices that should still work normally are:

Elgato Cam Link
Elgato Cam Link 4K

 

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Overall Solution

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The next major Windows update is expected for end of May.  Our developers are working on this issue, but right now, if someone moves up to 20H1, they will very likely see this problem

The only solution now would be to revert to an earlier build, like 19H1 or earlier.