How to reset the SMC on an Imac?
How to reset the SMC on an Imac? My fan is running at red line speed....
Intel-based Macs: Resetting the System Management Controller (SMC)...
http://support.apple.com/kb/HT3964
https://support.apple.com/en-us/HT201295
Or...
1.. Shut the machine down.
2.. UNPLUG the power lead to the computer and any peripheral devices.
3.. leave it for 10 minutes.
4.. Hold power Button in for 10 seconds
5.. Connect everything back up and restart.