Mac Mini display problem.

[richmond62]

Wow: about as OT as one get.

So . . . When I upgraded to MacOS 10.15.4 beta 6 yesterday my 3rd monitor connected via the 2nd Thunderbolt/USB-C connector
on my 2018 Mac Mini went blank and all connexions through that outlet 'went'.

Would be grateful if anyone has any bright ideas . . .
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Wonky port outlined in green.

[bogs]

I am sorry to say, Richmond, that I know less than nothing about Mac stuff, and so can't think of a situation where that might come up hardware wise short of failure. Of course, it would be curious that the failure would coincide with you updating the software, so the only thing I could suggest is to regress back to the software where it was working, possibly by starting off fresh with that Os version, and see if it is then 'working'.

If it is, then most likely it is something to do with the new version of the Os, which you can report I suspect to Apple, although what they would do with that report is again something I have no experience with.

[richmond62]

Well, for what it is worth, it turns out that the port in green seems to have stopped functioning . . .

as have successfully got my 3 monitors going again using the ones marked in orange (which the official Apple
documentation says it not possible) . . .

being technically fairly goofy, all I did was unplug and replug the contacts.
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[richmond62]

This is a problem that has already been reported by other people who
have upgraded their 2018 Mac Minis to MacOS 10.15.4 beta 6.

https://forums.macrumors.com/threads/lo ... 6.2227374/

[bogs]

As I said, pretty suspicious timing.

[richmond62]

Resetting the system management controller sorted that out . . .

Shut the machine down, yanked out the power cord, counted up to 30, plugged the power cord back in, restarted the thing.
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Mind you, I don't know why.