Mac mini M4 Pro sporadically loses connection with external monitor

Exact same issue with my M4 Mini and 2 identical Asus ProArt 27" 1440P displays. The HDMI connected display is fine, but the USB-C/Thunderbolt to DisplayPort one will not display with a system reboot. I must power cycle the monitor for it to display. I also bought the separate cable, since only a DP to DP cable was included in the box.

Extremely aggravating.

Hi there. I have signal issues too from my Mac Mini M4 . I have an Asus TUF Gaming VG28UQL1A - 28’ LED IPS UltraHD 4K 144 Hz Monitor , and since I’ve buyed my Mac Mini M4 & PS5 PRO ,both were connected via HDMI 2.1 with their own cables on the two HDMI 2.1 monitor ports ( have 2 hdmi 2.1 , 2 hdmi 2.0 & 1 dp 1.4 ports in total) and no issues,meaning both devices when powered ON apart , signal automatically appears on monitor (even on PS5 PRO from PS button controller). Also I want to say that i never turn OFF my monitor(never gives me problems on anterior PC gaming setup). I’m thinking now , if could have something to do with the Blackout ( I live in Spain and past week we had a Blackout for a few hours & caught me playing on PS5 PRO ,but my Mac Mini was OFF). I’ve tried with another HDMI cable on on each one of those 4 HDMI ports ,but still no signal (cause my monitor is turning OFF when i turn OFF the PS5 and only way is to turn ON monitor and switch to Mac HDMI port connection,but turning ON also is turning ON my PS5 ,so just manually changing. Another option is worked : took off PS5 cable from monitor & let only the Mac connected,but not allways working. I even buyed an USB-C to DP 1.4 cable,but no signal . I’ll try to see if i have to do some change on Mac to getting work.

Got the issue after updating to Sequoia 15.5 this morning on my Mac Mini M4 Pro (5/21/2025). Turns out the reason is the USB-C cable that came with the monitor is not a USB 4 (or Thunderbolt 4) or up. After I tried Thunderbolt 4 and 5 cables, the USB-C display connection back to normal. It was fine right before the update - might be some software requirement updated. Hope this helps!

I've been having similar issues.

Purchased my Mac Mini m4 base model on launch and a few times a week the screen goes blank for a few seconds then comes back.

Issue persists across an LG C1 TV, LG C4 TV and Dell ultra wide.

I've tried 3 different HDMI cables - all HDMI 2.1 certified, 2m and 1m in length.

I think it's the Mac itself at this point. Has anyone found a fix?

I, too, have just started to have issues with my Mac Mini M4 and a LG 27MD5KL-B 27 Inch UltraFine 5K monitor. The screen goes gray and it is temporarily fixed by replugging the cable from the monitor to the MacMini. The monitor seems to work fine with my old iMac, so I don't think the problem is with the monitor itself. I do wonder if the recent updates to the OS have introduced the problem with the video port on the MacMini. It would be extremely helpful is someone from Apple could identify the cause of the problem and a solution - whether if means waiting for another software update, change in cables, or using few external devices. Customers should not be the ones responsible for figuring the cause of the problem and a real solution.

My problem seems be fixed after purchasing a new Anker USB C cable - no more gray screens since it was installed! I'll find our for sure after doing some more intensive video editing.

https://www.amazon.com/dp/B09YM3V7NX?ref=ppx_yo2ov_dt_b_fed_asin_title

I bought an M4 for my brother and set it up at my house for him using a Sony 65” tv and it worked flawlessly.

when I hooked it all up at his house using a 27” Samsung monitor and a 50” Samsung tv using only new HDMI cables. It worked immediately on day 1. I put it to sleep when leaving and the next day it completely lost the signal and neither worked. I unplugged everything for 10 minutes then hooked it up and still nothing. I tried this for longer times in between attempts with no luck. The next day it worked again until it went to sleep after 1 hour and then no signal again.

I'm going to bring it back to my house and try it for several days to see what happens. Very frustrating as im trying to help my brother like the Mac mini and Apple products instead of windows products with no luck at all.

Im having the same issue too, but Im using a Thunderbolt Display with an adapter, when the mini m4 mac goes to sleep it never turns back on. I have to reboot the Mac mini from the button and then it glitches for a while. Im thinking it might be a Mac Mini issue.

Got new HDMI cable. Am hopeful n will add an update.

The old, non -4k monitor, hasn't had a flicker. Think that's a possibility? Just get a non-4k screen?

Not sure how to stop this from happening, but while in display settings, holding down the Option key and selecting "Detect Displays" fixes this on the fly (so far).

Not a consistent fix unfortunately.

I have an intermittent connection issue witht he hdmi connector. It seems a bit loose and I have to jiggle it for it to be connected properly.

Change out the HDMI cable.

For the best results get and use a short high speed certified HDMI cable.