Mac Mini 2011 boot problems

[srx00]

So, the problem started a few months ago and after months of research I couldn't find the solution. I'm asking now for an advice before I go to a proper Apple service.
The computer restarts sometimes after boot. When Apple logo appears, it just automatically restarts and then it boots normally.
The curious part is that when I boot to Windows via bootcamp, it boots normally. So, I have been using mostly Windows these last few months.
I nearly forgot about this, but I'm worried now because a new problem arrived:
After shutting down, both OS X and Windows, the computer turns itself back on. This also happens only sometimes.
What does this look like to you? Is it hardware or software problem?
I plan on replacing the HDD with SSD. Do you think this will help?

 

[keysofanxiety]

So, the problem started a few months ago and after months of research I couldn't find the solution. I'm asking now for an advice before I go to a proper Apple service.
The computer restarts sometimes after boot. When Apple logo appears, it just automatically restarts and then it boots normally.
The curious part is that when I boot to Windows via bootcamp, it boots normally. So, I have been using mostly Windows these last few months.
I nearly forgot about this, but I'm worried now because a new problem arrived:
After shutting down, both OS X and Windows, the computer turns itself back on. This also happens only sometimes.
What does this look like to you? Is it hardware or software problem?
I plan on replacing the HDD with SSD. Do you think this will help?

Sounds like it's kernel panicking before it boots into OS X. Best to see if it's hardware and work backwards. Boot into Windows and download the HD Tune Pro trial. Then please screenshot the 'Health' tab and upload it here, if it shows anything other than 'OK' at the bottom-left hand side: hdtunepro_560_trial.exe

If that comes back as OK at the bottom-left hand side, then the hard-drive probably doesn't have an issue. Shut down the machine. Hold CMD+R on startup to boot into OS X Utilities. Verify the disk through Disk Utility to see if there are any corruptions & repair them.

If you're still having issues or if it doesn't identify anything, you can select 'Reinstall OS X' in the OS X Utilities page. This will not wipe any of your data/applications, and will only reinstall the core OS components.

You can also try holding Shift on startup to boot into Safe Mode in OS X to see if it's something software related causing the issues.

 

[T'hain Esh Kelch]

Is your Windows installation on the same drive as the OS X installation?

 

[srx00]

Is your Windows installation on the same drive as the OS X installation?

It is.

I checked the hard drive with both Disk Utility in Recovery mode, and with HD Tune Pro. They are no signs of corruption.
I updated both Windows and OS X systems recently and the problem didn't go away. I will try again with reinstallation, maybe I didn't do something right the first time. It's hard to pinpoint the issue because it happens randomly.
Could it be something else hardware related?

 

[keysofanxiety]

Could it be something else hardware related?

Possibly RAM. If you've got a USB stick, you can boot into Windows and make a bootable stick. Then run MemTest x86 overnight by holding the Alt key on startup and selecting the USB drive: http://memtest.org/download/5.01/memtest86+-5.01.iso.zip

Edit: I think this one makes the process a little easier to pop straight onto USB: http://memtest.org/download/5.01/memtest86+-5.01.usb.installer.zip

 

[srx00]

Thanks! I will try that and then report any findings.

 

[srx00]

So, RAM is fine. I did a 3 pass check, and there were no errors.

 

[MikeatOSX]

Did you do a NVRAM or SMC reset?
https://support.apple.com/en-us/HT204063

When you replace the hard disk with a SSD, you should also replace the cheap PRAM battery.
https://www.ifixit.com/Guide/Mac+Mini+Mid+2011+PRAM+Battery+Replacement/6414

 

[srx00]

Resetting NVRAM and SMC doesn't fix the problem.
I will see about replacing the battery. But this is the first time that I hear about that fix. Is there any way to know for sure that I need to replace it? I would need to let the professional technician do that, and I want to try for other options before going there, especially because I'm not sure it will solve the problem.
Could it be an issue with Bootcamp? I ask this because the computer boots normally when booting into Windows. This problem only exist when using OS X.
Also, when booting through Safe Mode, everything works fine.

 

[MikeatOSX]

The mini will loose date & time (and some other settings) when started without Internet (time-lookup).
If not, the PRAM battery is ok.

 

[MikeatOSX]

Also, when booting through Safe Mode, everything works fine.

Sorry, saw it too late:
seems your OS X installation ist damaged, no hardware problem.

 

[sevoneone]

Is your 2011 Mini the model with the discrete AMD 6630M GPU? If so, it may be failing. The symptoms are exactly as you describe and I have had two minis die this way. The problem starts with random KPs while running GPU accelerated software, to requiring multiple reboots, to only booting to safe mode and ultimately being unable to boot OS X at all. For whatever reason OS X is much more sensitive to the problem than Windows and newer versions of OS X more so. You may have some luck getting Lion or Mountain Lion to run on it as they are not as GPU dependent as Mavericks and up... https://discussions.apple.com/thread/7059717?tstart=0

 

[srx00]

Is your 2011 Mini the model with the discrete AMD 6630M GPU? If so, it may be failing. The symptoms are exactly as you describe and I have had two minis die this way. The problem starts with random KPs while running GPU accelerated software, to requiring multiple reboots, to only booting to safe mode and ultimately being unable to boot OS X at all. For whatever reason OS X is much more sensitive to the problem than Windows and newer versions of OS X more so. You may have some luck getting Lion or Mountain Lion to run on it as they are not as GPU dependent as Mavericks and up... https://discussions.apple.com/thread/7059717?tstart=0

Yes, you are completely correct.
As it turns out, this was the issue. Unfortunately, there is no solution to it, other than changing the whole logic board...