Q: disk drive ejects

Try shutting down and restarting the drive. Do you have another computer you can test the drive on?

Try setting up another admin user account to see if the same problem continues. If Back-to-My Mac is selected in System Preferences, the Guest account will not work.

Isolating an issue by using another user account

If the problem is still there, try booting into the Safe Mode.  Shut down the computer and then power it back up. Immediately after hearing the startup chime, hold down the shift key and continue to hold it until the grey Apple icon and a progress bar appear. The boot up is significantly slower than normal.

Safe Mode

Safe Mode - About

General information.

Isolating issues in Mac OS X

Permissions Troubleshooting

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