External monitor detected issue after Big sur installed

Question

Created Nov ’20

Replies 3

Boosts 0

Participants 4

After Big sur installed, my MACbook pro could not detect external monitor (LG), tried plug, unplug, restart ...etc. One time suddenly external monitor displayed then off again.

I think this is Big Sur software problem. My external monitor works fine with Mac air and another Macbook (without Big sur installed).

Please help!

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Answer 1

plxfixthis OP

Nov ’20

i am experiencing this as well. there are people have been experiecing this for months on big sur beta, just read on reddit. how on earth was this allowed to be released like this with it occurring for months in beta?

my hp running windows detects the external monitors i am running, just fine. without zero issue. not a cable or a monitor issue.

i had recently upgraded to big sur and now this is occuring. was not occurring previously.

this is a big sur issue 100% and it has been going on for months now

1

Answer 2

123than OP

Dec ’20

I just ran into this as well. Pretty workflow breaking to be confined to only the laptop screen. I'm surprised (yet at the same time not surprised at all) that this would make it through to the official release. Hopefully a fix gets out soon...

My Setup:
macOS Big Sur v11.0.1
MacBook Pro (16", 2019) == TB3 ==> Plugable TBT3-UDZ == DP to HDMI ==> x2 ASUS VS238H-P

Monitors no longer detect any signal coming from MCB and the MBC is unable to detect monitors. I've gone through the whole array of standard troubleshooting steps; swap cables, test without dock, power cycle all the things in differing orders, etc.

0

Answer 3

double0seddon OP

Dec ’20

Same problem here. Using a VGA to thunderbolt adapter. Some are saying the problem relates to it not being an Apple product. Worked for a few days after the update but suddenly stopped working at about midday today.
Reassuring to see its an Apple problem but it would be great to see some suggested fixes here, particularly from Apple themselves.

Colin

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