Mac mini (mid 2011_High Sierra) restarts by itself periodically when monitor switched off only

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Mac mini (mid 2011_High Sierra) restarts by itself periodically when monitor switched off only

Hi, my Mac mini (mid 2011_High Sierra) restarts by itself periodically.

I searched different sources, tried different options, including Safe mode restart, switched off everithing - the only reason I found is:

when macmini connected to the monitor and the monitor is switched off or use different input - restarts periodically (several times a day),
when monitor on (no sleep mode in monitor) - no problem.

Monitor connected through mini-dvi cable.

wi-fi, safe mode, power saving settings or other options have no influence on this.

What should I do?

Posted on Apr 17, 2020 6:44 AM

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Answer 1

Top-ranking reply

den.thed

Level 10

91,414 points

Apr 17, 2020 7:34 AM in response to rustem224

Try resetting the SMC, as per > How to reset the SMC of your Mac - Apple Support

and then the NVRAM, as per > Reset NVRAM or PRAM on your Mac - Apple Support

If those do not help, please tell

What monitor you have?
What other inputs it supports?
What Mini DisplayPort to ??? cable you use?

Sounds like you need to use an active Mini DisplayPort to ??? adapter. That way the Mac Mini will aways see the adapter, instead of no monitor on the end of the Mini DisplayPort to ??? cable.

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Answer 2

den.thed

Level 10

91,414 points

Apr 17, 2020 9:14 AM in response to rustem224

You are confusing Mini DisplayPort and DisplayPort with Mini-DVI.

see > https://www.dell.com/en-us/work/shop/accessories/apd/210-agnk?gacd=9646510-1028-5761040-0-0&dgc=st&gclid=EAIaIQobChMIj6X-gOvv6AIVExvnCh2gJwzSEAAYASAAEgLqpvD_BwE&gclsrc=aw.ds

The 2011 Mac Mini also has a Mini DisplayPort not Mini-DVI.

It is starting to sound like the Dell monitor has some feed back or crossover between it's Mini DisplayPort and DisplayPort input ports, which is causing a problem for the Mac Mini.

What happens when you switch to an HDMI cable between the Mac Mini and Dell monitor?

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Answer 3

rustem224 Author

Level 1

9 points

Apr 21, 2020 10:21 AM in response to rustem224

Try resetting the SMC, as per > How to reset the SMC of your Mac - Apple Support

and then the NVRAM, as per > Reset NVRAM or PRAM on your Mac - Apple Support

No difference. I even reload High Sierra from my last year backup. Not helped.

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Answer 4

rustem224 Author

Level 1

9 points

Apr 17, 2020 8:20 AM in response to den.thed

Resetting didn't help. Tried already.

My monitor is Dell P2715Q (with Dvi, mini-dvi, HDMI inputs). I use two desktops - Mac mini and HP and switch between them.
See above, mac connected to mini-dvi, HP connected to DVI.
No adapters - all connections are direct (mini-dvi to mini-dvi on mac), (DVI-DVI HP).

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Answer 5

rustem224 Author

Level 1

9 points

Apr 21, 2020 10:19 AM in response to den.thed

My monitor is Dell P2715Q (with Display, mini-display, HDMI inputs). I use two desktops - Mac mini (mini display port) and HP (display port) and switch between them.
No adapters - all connections are direct cables.
Problem stays if I switch Mac to Display port (mini display - Display).

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Answer 6

Apr 22, 2020 8:36 AM in response to rustem224

When you found the problem for first time?

Did you try clean install?

Did you try an older OS?

I have very similar problem with similar machine. Is your Mac mini equipped with dedicated GPU?

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