M4 Mac Mini stuck in start-up loop due to Thunderbolt issue

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M4 Mac Mini stuck in start-up loop due to Thunderbolt issue

I've plugging two powered WD Elements drives through to my a new Dell UltraSharp U2715H 27" 1440p Monitor. The monitor (also powered) acts as a hub, with the Elements drives plugged into it and then connected to the M4 Mac Mini Pro via Thunderbolt.

It will work for awhile but eventually I'll get a flashing orange power light, the Mac Mini shuts down and then it sends my Mac Mini into an eternal start up loop until I disconnect the drives from my hub.

The fact everything is powered says to me it isn't a bus overload issue.

I can plug the exact same hub configuration into my M1 MacBook Pro and it works flawlessly.

I'm seeing other customers experiencing a similar issue with all sorts of different drive and hub configurations. You should be able to plug any drive or hub into a Thunderbolt port and it not send your Mini into a start up loop.

Extremely disappointed with what is obviously a hardware issue on Apple's end. I would like a solution as I bought the monitor and M4 Mac Mini at the same time to run this setup.

Posted on Mar 4, 2025 04:28 PM

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Answer 1

den.thed

Level 10

88,840 points

Mar 6, 2025 12:00 PM in response to Wozowski

Wozowski wrote:

You can't 'directly' plug them in because they aren't USBC / Thunderbolt. You need either a dongle or a hub, hence the monitor.

Why, what are you thinking?

That’s exactly what I was thinking.

One WD drive connected to the monitor and one WD drive connected directly to the Mac mini using a USB-C to USB-A adapter.

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Answer 2

Wozowski Author

Level 1

10 points

Mar 6, 2025 01:46 PM in response to den.thed

Yeah I get that, but why? What is the process of elimination you are getting at?

Are you suggesting that the two drives through a thunderbolt connected hub are too much? They really shouldn't be, especially if it is powered. These ports are supposedly made for this exact scenario.

I'll do it, but this issue isn't 100% frequent. So replicating it can be tricky and may take a day or two.

To know whether this works is also tricky, because I'll need to wait a week or so to see if I get no shut downs and loops.

I currently experience this 2-3 times a week.

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Answer 3

den.thed

Level 10

88,840 points

Mar 6, 2025 01:58 PM in response to Wozowski

Wozowski wrote:

Yeah I get that, but why? What is the process of elimination you are getting at?

Testing different setups is the only way to find the problem.

Are you suggesting that the two drives through a thunderbolt connected hub are too much? They really shouldn't be, especially if it is powered. These ports are supposedly made for this exact scenario.

What Hub...? Initially you said that the WD drives were connected thru the Dell UltraSharp U2715H.

I'll do it, but this issue isn't 100% frequent. So replicating it can be tricky and may take a day or two.

To know whether this works is also tricky, because I'll need to wait a week or so to see if I get no shut downs and loops.

I currently experience this 2-3 times a week.

Only experimenting and time will tell.

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Answer 4

Wozowski Author

Level 1

10 points

Mar 6, 2025 02:54 PM in response to den.thed

Looks like I listed the wrong monitor. My bad.

It is this one - https://www.dell.com/en-au/shop/dell-ultrasharp-27-thunderbolt-hub-monitor-u2724de/apd/210-bkmd/monitors-monitor-accessories

The Dell U2724DE UltraSharp 27 is a hub. Has ports out the back for connecting 3xUSB-A devices, Ethernet, etc. along with Thunderbolt upstream and downstream.

I'll try it and come back in a week if my Mini doesn't go into the restart loop.

I will say, 'Maybe it's the monitor.' isn't an answer. These things should work, and do work on my M1 MacBook Pro. Other people are experiencing the exact same problem as me, including those who had the same set up working flawlessly on older Mac Mini models.

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Answer 5

den.thed

Level 10

88,840 points

Mar 6, 2025 03:55 PM in response to Wozowski

Wozowski wrote:

Looks like I listed the wrong monitor. My bad.

It is this one - https://www.dell.com/en-au/shop/dell-ultrasharp-27-thunderbolt-hub-monitor-u2724de/apd/210-bkmd/monitors-monitor-accessories

The Dell U2724DE UltraSharp 27 is a hub. Has ports out the back for connecting 3xUSB-A devices, Ethernet, etc. along with Thunderbolt upstream and downstream.

No problem.

I'll try it and come back in a week if my Mini doesn't go into the restart loop.

Take your time.

I will say, 'Maybe it's the monitor.' isn't an answer. These things should work, and do work on my M1 MacBook Pro. Other people are experiencing the exact same problem as me, including those who had the same set up working flawlessly on older Mac Mini models.

I do not think so ether. One difference that I'm getting, is that these new Mac mini's do not manage port power the same way as the earlier MacBook Pro's and Mac mini's did.

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Answer 6

Wozowski Author

Level 1

10 points

Mar 12, 2025 05:03 PM in response to den.thed

A quick update.

Unplugged a drive and plugged it into my Satechi USB3 dongle leaving the other plugged into the hub.

The drive plugged into the Satechi won't mount through the rear Mac Mini thunderbolt ports at all. But does mount on my Macbook Pro flawlessly. I've never had any issue with this dongle.

The remaining drive going through the hub on my monitor didn't send my Mac Mini into a orange flashing light shut down. BUT, when I restarted the Mac Mini it did go into the restart loop until it was unplugged.

I then swapped both drives over, just to make double sure. I get the exact same result, leaving me thinking the Thunderbolt 5 ports on the back of my Mac Mini are funky AF.

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