iMac: If You Cant Eject a CD or DVD, or Open the Drive Tray

via Apple Support

 

Resolution

Important: Make sure the disc is not in use. Quit all applications that are using files on the disc.

1. Place the computer in sleep mode.

2. Press the Media Eject key at the top-right corner of the keyboard.

3. If that doesn’t work, drag the disc’s icon to the Trash.

4. If that doesn’t work, restart the computer, then hold down the mouse button.

5. To restart, choose Restart from the Apple menu.

Repair Disk Permissions

Occasionally in OS X  file ownership and permissions get changed by applications and program installers.  When ownership and permissions get changed, things just don’t work as they should.

The symptoms might be programs quitting unexpectedly, preferences not being remembered, programs not launching, etc. This is where Repair Disk Permissions utility comes in.

To repair permissions, open the Disk Utility program found in the Applications/Utility folder on your hard drive. At the top of the Disk Utility window is a row of tabs.  Click on the First Aid tab.  On the left is a list of the disk and volumes mounted on your computer system.

You need to click to highlight your main hard drive. In the right window pane in the lower left click on the repair disk permission. After the repair you can restart your Mac. I would also recommend running this repair after each new software update runs.

 

Resetting the PRAM

Resetting the PRAM

This is a common Mac troubleshooting procedure, and fixes a multitude of software and hardware problems.

PRAM stands for Parameter RAM, and contains the following stored information:

Display and video settings such as refresh rate, screen resolution, number of colors

Time zone setting

Startup volume choice

Speaker volume

Recent kernel panic information, if any

You will not lose any data stored on your Macs drives, and system and application preferences besides the above will remain intact.

 

How to Reset your PRAM

Reboot your Mac

Hold down Command Apple – Option Alt – P – R

When you have heard the chime for the second time, release the keys and the Mac will boot as normal

Once your operating system has loaded, you may need to verify your time zone, startup volume, and volume settings using System Preferences