Catalina USB-C to HDMI not working

[Petr Molek]

Hi,

Ever since Catalina was released, my DELL USB-C -> HDMI dongle stopped working.
It works fine under windows, but when connected to macOS, it works only for a few seconds and then the whole external screen turns blue.
Please note that this adapter doest not use DisplayLink!

There is also a thread on Apple forums, but no solution has been provided: https://discussions.apple.com/thread/250715642

Did anyone ever solve this? From the internet it seems like half of the adapters work and half doesn't.

Thanks!

 

[MacGizmo]

I don't think that's a Catalina problem (though it could be). I had a similar issue a few years ago. Adapters are just garbage. It doesn't matter who makes them, how long they worked fine... eventually they will just up and die, or stop working on this machine or that one for no reason at all.

 

[me55]

I've been using a relatively cheap adapter cable (this one) for a while and it works 100% fine. I remember reading that some Dell USB C adapter is finicky even on Dell machines, don't recall if it was this one.

 

[tommiy]

Yes similar experience but only with Catalina. Updated and the MAC no longer liked the cable it worked the last 2 years with. I ended up becoming a testing ground for Apple trying to find a cable that would successfully work. Got to be on first name basis with local supplier as I tried and returned many cables. Eventually I found an Alogic cable that worked. I had tried even much more expensive cables that did not work so price is not the point to determine functionality.