Q: How do I switch back to mac OSX from windows 8.1

Startup your Mac while holding down the Option key.

That should prompt the Startup Manager window where you can select OS X then click Restart.

Either use the Startup Disk control panel in Windows or:

Boot Using OPTION key:

  1. Restart the computer.

  2. Immediately after the chime press and hold down the

      "OPTION" key.

  3. Release the key when the boot manager appears.

  4. Select the OS X disk (not the Recovery HD disk.)

  5. Click on the arrow button below the icon.

Use the Alt key or try the Windows key.

From Windows back to OSX:  You should have a shortcut in the tray, right click it, choose "Restart In OSX"

From OSX back to Windows:  Install an OSX app called BootChamp which will put a shortcut icon on the top menu bar, click it, choose "Restart in Windows"

I use these two taskbar shortcuts to do all my operating system hopping....