Mac Mini keeps restarting

My Mac is continuously restarting, often without finishing the previous restart cycle.

Mac Mini 2.7GHz quad-core Intel Core i7, 8Gb RAM (aftermarket Crucial 2 x 4Gb), aftermarket Crucial 512 Gb SSD running El Capitan

Steps so far:

Reset PRAM and unplugged-replugged power cord. -> -> No change. Mini keeps restarting.
Disconnected all peripherals, even monitor, keyboard and mouse -> No change. Mini keeps playing reboot chord.
Re-installed original internal hard drive, running Yosemite. -> No change. Mini keeps restarting.
Removed aftermarket (Crucial) RAM and re-installed original RAM chips (2 x 2G). -> No change. Mini keeps restarting.
Re-installed aftermarket Crucial SSD. Reformatted drive and did clean system install. -> -> No change. Mini keeps restarting even during the "new install setup" cycle.

So far, the only way to keep Mini running is by "safe boot", which renders it unusable for most purposes.

Can't afford a new Mac right now. Any suggestions?

Thanks!!

Seems you have already done quite a bit of great troubleshooting! I can't think of a whole lot else to try…but here are a few things:

1. This may sound crazy…but is there anything wrong with the power button. I'm wondering if the power button is failing…or is stuck somehow.
2. Maybe try resetting the ram (remove & reinstall the ram).
3. Try starting the Mac-Mini with only 1 stick of ram installed (swap each stick as necessary).

HTH,

- Nick

Thanks!
I tried disconnecting the power cord and pushing the power button a few times in case it was stuck, but it seems to be OK in that it turns the machine on or off when pressed.
I tried replacing the RAM and running the Mini with one stick -trying each RAM socket. No dice!

Too bad nothing helped. Generally I would say reinstall the OS…but it sounds like you already did that…plus trying two different drives. The fact that you tied two different drives (each with their own OS installed on it)…would seem to indicate a hardware issue of some sort (not OS or hard drive/SSD related).

By the way…I'm going to assume this is a 2012 Mac-Mini. Since I think this is the only Mac-Mini model with a quad-core cpu.

Here's an interesting article that seems to be related to your situation. Maybe it can be of some help:

http://www.cnet.com/news/how-to-address-a-constant-reboot-loop-in-os-x/

- Nick

pigoo3 said:

Too bad nothing helped. Generally I would say reinstall the OS…but it sounds like you already did that…plus trying two different drives. The fact that you tied two different drives (each with their own OS installed on it)…would seem to indicate a hardware issue of some sort (not OS or hard drive/SSD related).

By the way…I'm going to assume this is a 2012 Mac-Mini. Since I think this is the only Mac-Mini model with a quad-core cpu.

Here's an interesting article that seems to be related to your situation. Maybe it can be of some help:

http://www.cnet.com/news/how-to-address-a-constant-reboot-loop-in-os-x/

- Nick

Click to expand...

Thanks for the excellent article Nick. It pretty much tells me what I have been expecting:

"First try booting to Safe Mode by holding down a Shift key when the system restarts. If the computer is able to boot properly, then you know the issue is likely with some third-party extension or add-on you have installed. This is especially true if the system only boots to Safe Mode and continues its reboot loop when you restart without the Shift key held down."

My case, except for the matter with third party extensions. I have been doing clean installs (without non-apple elements) with two different hard disks -while becoming an expert in poking inside the Mini- with the same results.

"If the system shows the same behavior when booting to a different boot drive (especially to the OS X installation drive), then it suggests a hardware fault is to blame for the problem, and not something to do with a configuration of the operating system. In this case, you can try resetting the PRAM and SMC for your system, but beyond that you will likely need to have the system serviced."

That's what's happening here. Too bad because it is a really nice Mini (Mid 2011 with an i7, CPU which I ordered from Apple with the 2.7 Ghz option). I have an older Mini, whose motherboard also went south seven years ago. Replacement boards for it can be found on eBay for about $90 while boards for the newer model cost around $500. So I'll try fixing the older Mini, which will hopefully hang on till I can afford a new Power Book with all the trimmings. The newer Mini will go into storage until prices for replacement parts come down.

Thanks so much for your advice!

Luis

You're welcome. Good luck with the project. Please let us know how things go.

- Nick

Just to report what seems like a success - so far ... Mac Mini mid-2011 running High Sierra repeated rebooting during boot sequence ...

I read a suggestion on another thread - about deleting cache files ... so I used Parallels Toolbox's component 'Clean Drive' and allowed it to clean up my Log Files and Cache Files ... and 'touch wood' so far I have had all 'clean' single boot and restart sequences so far ...

If the Mac keeps rebooting after displaying the Apple logo, there may be a problem with the kernel extension, which prevents the system from booting normally. ...First try to boot into safe mode while holding the Shift key while the system restarts