My Mac Mini will not boot !... -:((

[mafaky]

I had upgraded my Mac Mini to Yosemite, a while ago and running without any problems till today.

Now it doesn't boot up at all. I removed all peripheral cables (except the monitor), turned off the Mini, waited for 30 seconds or so, turned on (push the switch at the back corner) again, and as soon as I hear the startup sound start pressing the Shift key. First I get a totally blank grey screen. After 15-20 seconds the monitor changes to the black screen and I get the prompt: "no boot device available -- insert boot disc and press any key"

What's the remedy?

Thanks for the assistance as I'm still a newbee at Mac/OS X.

 

[Fishrrman]

1. Power down (all the way off)
2. Reboot
3. As soon as you hear the startup sound, hold down the option key and KEEP HOLDING IT DOWN.
4. In a few moments, the startup manager should appear.

What choices does it give you?

 

[ApfelKuchen]

I had upgraded my Mac Mini to Yosemite, a while ago and running without any problems till today.

Now it doesn't boot up at all. I removed all peripheral cables (except the monitor), turned off the Mini, waited for 30 seconds or so, turned on (push the switch at the back corner) again, and as soon as I hear the startup sound start pressing the Shift key. First I get a totally blank grey screen. After 15-20 seconds the monitor changes to the black screen and I get the prompt: "no boot device available -- insert boot disc and press any key"

What's the remedy?

Thanks for the assistance as I'm still a newbee at Mac/OS X.

There are several possible causes, hence several possible solutions.

So far, you've followed the first two steps found in http://support.apple.com/en-us/TS2570 - The next step? Reset the NVRAM - http://support.apple.com/en-us/HT204063

If that doesn't resolve, then switch to another document - http://support.apple.com/en-us/HT4718 - Boot to Recovery, then use Disk Utility to test the HDD http://support.apple.com/en-us/HT203176

If the system can't find a boot device, it means there could be something wrong with either the system's ability to locate the hard drive, or the hard drive itself.

Resetting NVRAM addresses the system's ability to locate the hard drive, Disk Utility will diagnose problems with the hard drive.

 

[h9826790]

Did you choose Windows (bootcamp) as your start up disk?

If yes, perform a PRAM reset, that will bring you back to OSX.