I switched on my mac after 14 hours ago when it was working fine, now there is no life except for a grey screen, apple logo and a revolving cog. Does anyone have any ideas? Thanks in advance.
Try a safe boot by holding down the Shift key between the startup sound and Apple logo/spinning cog.
It will take longer to boot up this way but a progress indicator should appear.
I this works, Go to System Preferences > Startup Disk > select your boot disk and restart.
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