macOS Monterey 12.4 (21F79) - Unable to recognize external monitor (LG)

Hi Cali_NW_MRY,

Welcome to Apple Support Communities. Great troubleshooting so far. Check out If your external display isn't detected or appears blurry when connected to your Mac which has a couple more tips that might help.

If the same continues, try resetting the SMC which can help if the issue is power-related- How to reset the SMC of your Mac.

Best of luck.

Hello Cali_NW_MRY,

Have you installed the latest driver for the display? Looks like LG recently released a driver for Mac on 5/31/22: https://www.lg.com/support/product/lg-38UC99-W.AUS You'll see the driver on the right side of the website under Software & Drivers.

Once you've installed the driver, reconnect the display and attempt to test it out.

Let us know if that helps to solve this, cheers.

I'm also having this exact problem with 2 different monitors and two different connection types. Both were working fine until the day after my Macbook updated.

We understand Cali_NW_MRY,

At this point, we recommend reaching out to Apple for further assistance in resolving this issue here: Get Support

Cheers!

Same issue as above! External monitor no longer working with USB-C. Also, my Ethernet port adapter not reading either.