iMac no longer recognizing Samsung monitor

Question

Level 1

4 points

iMac no longer recognizing Samsung monitor

I have a 2023 iMac M3 that I am attempting to (re)connect to an external Samsung U28E510D monitor, with a HDMI cable connected to an Inkling USB C adaptor from the iMac. I had the Samsung monitor connected and recognized for 4 months. I left my office for two weeks, shut down the Samsung monitor and the iMac. Since returning I have been unable to get my iMac to (re)recognize the Samsung monitor.

Relevant details:

-I have checked the make sure it's not a problem with the USB C adaptor. The adaptor is working properly.

-I have restarted both iMac and Samsung monitor multiple times.

-I have tried all input channels on Samsung monitor.

-On my Mac I have accessed System Settings>Displays>Hold option key>Click Detect Displays ("Detect Displays" darkens when clicked but nothing happens).

-I have unplugged the display from my Mac and plugged it back in.

-I have made sure the cable is securely connected to the correct port.

-I am using the same cable for the display as I was using before, when it was working.

-I am using the same functioning adaptor (Inkling USB C) as I was using before.

-I have put iMac to sleep and woken it back up.

Thank you for any ideas or suggestions on how to fix this.

iMac 24″, macOS 14.2

Posted on Mar 19, 2024 10:37 AM

Reply

Answer 1

rkaufmann87

Level 10

149,098 points

Mar 19, 2024 11:11 AM in response to Prinz89

Please restart the computer in Safe Mode (have the keyboard charging cable plugged in) with ALL external peripherals disconnected. Then add one, test it, then add the next and test, rinse and repeat until done!

2 other things,

Never use Sleep.

BTW, do you have any of the following third party apps installed on your Mac?

· Antivirus Apps

· Cleaning Apps

· Security Apps

· VPN Apps

· Maintenance Apps

Reply

Answer 2

rkaufmann87

Level 10

149,098 points

Mar 19, 2024 12:44 PM in response to Prinz89

Uninstall the VPN app , restart in Safe Mode , add the Samsung…test.

Reply

Answer 3

Prinz89 Author

Level 1

4 points

Mar 19, 2024 11:32 AM in response to rkaufmann87

Thank you. I restarted in Safe Mode with all external peripherals disconnected. I added and tested one by one. All external peripherals are working, other than the Samsung monitor.

The only third party app I have installed is a VPN app. The VPN was not and has not been activated during my attempts to connect the Samsung display.

I never heard the advice to never use sleep mode. Thank you and I will research more.

Reply

Answer 4

Prinz89 Author

Level 1

4 points

Mar 21, 2024 9:10 AM in response to rkaufmann87

Thank you. I uninstalled the VPN app, restarted in Safe Mode, and added the Samsung Monitor. Still nothing. When I disconnect the HDMI cable, the monitor goes from black (displaying HDMI 1 in the top left corner), to displaying a floating "check signal cable" box. When I reconnect the cable, the screen goes back to black, with the power light flashing blue in the bottom left corner.

So it would seem that the monitor is being recognized in some capacity.

Reply

iMac no longer recognizing Samsung monitor

Similar questions