Late 2013 Macbook Pro will not boot with MacOS Big Sur if connected to external monitor.

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Level 1

9 points

Late 2013 Macbook Pro will not boot with MacOS Big Sur if connected to external monitor.

While connected to an external monitor with a Thunderbolt cable, a late 2013 Macbook Pro crashed when installing MacOs Big Sur. To make a long story shorter, eventually MacOs Big Sur was installed when the external monitor was disconnected. However, now the late 2013 Macbook Pro will not boot with MacOS Big Sur while connected to the external monitor. The Macbook Pro turns on, but the Apple icon never appears, and the computer hangs with a dark gray screen. If the external monitor is disconnected, the MacBook Pro boots MacOS Big Sur, and then the external monitor can be connected, and the reconnected external monitor works.

MacBook Pro 15″, macOS 11.0

Posted on Nov 16, 2020 10:31 AM

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Answer 1

Best reply

etienne68yellow

Level 1

18 points

Dec 15, 2020 11:24 AM in response to TimPS

ALL SORTED...

I spent hours on the phone with Apple Ireland about this issue last week and they remotely took over my Macbook Pro and did loads of unfathomable tech stuff as I watched, including taking time-stamps of actions they did, as they occurred in real time.

They rang me to let me know that they were about to release macOS Big Sur 11.1 and that the engineers had inserted some coding to hopefully sort my/your issue.

They rang again tonight and asked me to download, install and restart to test it, and they waited while the install occurred etc.

And it works.... Macbook now happily reboots with Thunderbolt monitor attached, etc

Feel free to send me £10 notes in brown envelopes to show your eternal gratitude ;O)

Happy Christmas one and all.

Giles

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Answer 2

BDAqua

Level 10

239,531 points

Nov 16, 2020 10:53 AM in response to TimPS

Safe Boot, (holding Shift key down at startup), does the problem occur in Safe Mode?

Safe mode attempts to repair Disks & clears lots of caches & loads safe Drivers, & prevents loading of 3rd party extensions, so if Safe Mode works try again in regular boot.

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Answer 3

TimPS Author

Level 1

9 points

Nov 17, 2020 9:39 PM in response to BDAqua

When connected to an external 27" Apple monitor with Thunderbolt, this late 2013 MacBook Pro will not boot in safe mode. It will boot if the external monitor is disconnected.

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