Advice please - Mac not waking from sleep.

Discussion in 'Mac Basics and Help' started by peter@pjandj.karoo, Sep 21, 2015.

  1. peter@pjandj.karoo macrumors newbie

    Sep 21, 2015
    I am using a desktop OSX version 10.7.5. Each night I exit my desktop icons and put the system to "sleep" (not shut down). Normally my computer springs back to life when I touch the mouse, space-bar or any other key.

    Over the last few days the computer has not re-awakened when I press the mouse or a key.

    I have to switch off the computer using the button at the back of the screen - and then re-boot the system from scratch. This takes time for everything to re-load and I do not know why it has suddenly started happening - for no apparent reason.

    Can anyone help please ?
  2. chscag macrumors 68030


    Feb 17, 2008
    Fort Worth, Texas
    Reset the SMC (System Management Controller). Shut down your iMac and remove it from the mains. Let it set that way for about 10 minutes, then attach it once more to the mains and restart. Test the sleep wake cycle to see if it's working correctly.

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