I recently updated my MacBook Pro 14” (M2) to macOS Tahoe. Since the update, my external display is not being detected when connected via HDMI. However, if I connect my iPad as an external display, both the iPad and the external monitor work. Once the iPad is disconnected, the external display also stops working.
[Re-Titled by Moderator]
Original Title: Tahoe external display not detected
MacBook Pro 14″, macOS 26.0
macOS has become progressively less tolerant of video data packet loss due to sub-par cables. There have been several reports of setups that worked in Sequoia not working in Tahoe, with nothing changed but macOS.
Best recommendation at this point is to try a new cable. Be sure to high quality cables (HDMI should be labeled Ultra or Premium, USB-C cables should be rated for high-speed data transfer), and cables should be as short as possible (≤1 m, ideally...for Thunderbolt 5, ≤0.5 m). A random cable you found in a drawer might or might not work.
Thankyou, this worked for me.
I have the same issue. I've used USB-C cables directly from Apple and LG, and this still does not resolve this problem.
Do you have an M chip macbook or 2020 or older
Every time I update the system to a new stable release the HDMI port stops working properly. It can work for three days with one monitor and then it just stops. Usually it detects the external monitor but the signal is not going through. But... it works through an HDMI to usb-c adapter.
I bought the M1 Pro 14 for two things: the camera (all other macbooks had terrible camera back then) and the HDMI port. And after each release there are problems with both of them...
Totally agree. I've also upgraded to Tahoe, 26.0.1 bought different types of HDMI cable (female to male) - 4K and 8K, as well as a type c to hdmi coverter. It all didnt work in Tahoe 26.0.1 version, with the same exact setup, when boot in safe mode, Macbook Pro could pick up the external display again. Extremely frustrating trying to understand what's wrong.
External display not detected after macOS Tahoe update via HDMI
