MacMini m4 2025 LED shows SOS in morse code

You should leave your computer permanently attached to the mains power otherwise a tiny battery inside it can fail.

• AI Info: CMOS Battery's Role:
• The CMOS battery provides power to the CMOS RAM (Complementary Metal-Oxide Semiconductor Random-Access Memory), which stores the BIOS settings (like date, time, boot order, etc.) and the RTC. 
• Power Consumption When Unplugged:
• Even when the PC is unplugged, a small amount of power is still needed to keep the RTC running and the CMOS settings in memory. 
• Impact of Disconnecting Power:
• Regularly disconnecting and reconnecting the PC will contribute to a slightly faster discharge of the CMOS battery, compared to a PC that is always plugged in and off.However, this effect is usually minimal and the battery is still expected to last for many years, according to Linus Tech Tips and others. 

Correct: Mac computer status indicator light behavior - Apple Support

"To isolate the issue, run Apple Diagnostics."

AD is of limited use in such circumstances because only two outcomes are possible: it will conclude "no trouble found" in obvious contradiction of your observations, or it will conclusively identify a hardware fault that only Apple will be able to fix. In either case a trip to the Genius Bar will be required.

Official Apple Support

It is not clear to me if that Mac was merely powered down or completely disconnected from mains power for a long time (weeks or months) but routinely disconnecting desktop Macs from mains power is not beneficial.

Yeah I left a couple of old laptops and my 2009 iMac disconnected from power for like 10 years and eventually the CMOS battery failed in all three of them. Which meant they could no longer keep the time.

Obviously I have other newer machines connected to the mains power in daily use so I won’t have that problem with them. Replacing a CMOS battery on a PC motherboard is easy but I wouldn’t fancy doing it on a laptop or a Mac mini.

Anyway it would take a long time for this to happen and no Mac mini m4 would have this happen as they are so new even if left disconnected from mains for the last six months.

If you think you have a hardware issue, then contact Apple Support or your local AASP.

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MacMini_M4 wrote:

MacMini m4 bought in 2025 sitting on the shelf with power switched off. After I switched on the power the LED was blinking orange and I realized it was SOS in morse code ... _ _ _ ...

MacMini wouldn't turn on. So I switched power off again and tried to restart. Eventually it worked, but now it happened a second time. I think this is a hardware issue, right?

The Blinking Orange Light is a indicator that the Security Chip is not working properly

That could be a hardware issue or something else

Rarely, a Mac with Apple silicon or the Apple T2 Security Chip might stop responding and need its firmware to be revived or restored by another Mac.

An aside

I purchased the M4 Mac Mini on day of release Oct 30, 2024

It has worked better than expected and at least better than the M1 Mac Mini I used as part of Trade In

Personally, I keep the M4 Plugged in to a APC Back-UPS Pro 1350VA, 120V, AVR, LCD, 2 USB charging ports, 10 NEMA outlets (4 surge) All the time

The UPS in turn is keeps ON all the time

Should there be an electrical outage in my area, it does not negatively affect the Mac Mini in any way

Why are you cutting off the power to the Mac mini..?

The Mac mini should be shut down with the power left on...

or optionally left powered on with just the display set to turn off...