Question PC not recognizing second monitor anymore

Aug 14, 2022
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Hi all,

After some cable management, my second monitor has stopped being recognized by my PC.

I have a dual monitor (both dell u2312hm) set-up connected to both my windows 10 PC (GTX 770 GPU) and my MacBook pro (2019).

The set up is:
  1. Monitor 1 (dell u2312hm):
    • DP switch
    • USB-c male to DP male from MacBook to switch
    • DP male to DP male from PC to switch
    • DP male to DP male from switch to monitor
  2. Monitor 2 (dell u2312hm):
    • HMDI switch
    • HDMI male to HDMI male from USB-c hub (connected to Mac) to switch
    • HDMI male to HDMI male from PC to switch
    • HDMI male to DVI male from switch to monitor
For months there were no issues with this set-up. After some cable management, my second monitor is not recognized by my PC but my dual set up still works the same for my Mac.

Things I've tried:
  • New HDMI cable from PC to switch - same thing as using the old cable
  • HDMI male to DVI male from PC directly to monitor - simply no display on the second monitor
  • Switching the setups between monitors - I switch the DP switch to monitor 2 and the HDMI male to DVI male from PC to monitor 1 directly; monitor 1 input was not detected but monitor 2 worked fine
  • Trying a completely different Dell monitor (so one is u2312hm and the other I'm not sure but it has a HDMI port and a VGA port) - the second monitor actually works as the set up used to work though in this case I am using HDMI male to male from hdmi switch to the monitor as this monitor does not have a DVI port
  • Swapping the HDMI male to DVI male for a HDMI male to HDMI male with a HDMI to DVI adapter from the switch to the monitor - same thing as using the previous cable
  • Reinstalling GPU drivers and monitor drivers - I previously did not have dell specific monitor drivers installed and the installation only detects one monitor
  • In every scenario the Mac works fine
I really don't understand what's going on. The set up was working fine for months until I did some cable management. I disconnected and reconnected wires during the cable management but that's it. No hardware or software changes.

It's weird that it was working fine before and it's weird that it still works fine with my MacBook.

Any help is appreciated
 
Last edited:

DRagor

Illustrious
In cases like this details are super important. Please edit your post in Things I tried section with exact details of what's happening at each of those steps. Particularly what's happening when you switched monitors - did the problem follow monitor or cable? Does MacBook works with all those setups you tried?
 
Reactions: Helppls52
Aug 14, 2022
3
1
15
0
In cases like this details are super important. Please edit your post in Things I tried section with exact details of what's happening at each of those steps. Particularly what's happening when you switched monitors - did the problem follow monitor or cable? Does MacBook works with all those setups you tried?
Thank you I have updated my post, the problems seem to follow the u2312hm monitors
 
Aug 14, 2022
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Update:

Regarding this point:

Swapping the HDMI male to DVI male for a HDMI male to HDMI male with a HDMI to DVI adapter from the switch to the monitor - same thing as using the previous cable
I forgot to change the switch to the correct monitor, so this method works. I tried this method because I read somewhere that a HDMI male to DVI male cable is not a HDMI male compliant cable.

Leaving this in case it helps others.
 
Reactions: DRagor

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