My mac keeps ejecting any dvd i put in?

Because this could go in the way of a hardware issue or be an issue with the types of DVDs you are using (even legal and commercial copies), so I have three procedures below, I would suggest you try, in order to resolve your Macbook issue with auto-ejecting DVDs.

Procedure #1
-PRAM RESET-
The Parameter RAM Reset is a good troubleshooting process for working with various functions including refresh rate, screen resolutions, and DVD region issues to name a few.

Steps:
• First, shut your Macbook down properly
• Once your Mac is shutdown, locate the following keys on the keyboard:
Command, Option, P, and R.

You will need to hold those keys down simultaneously .

• Now turn on the Macbook.
• Press and hold the Command-Option-P-R keys.

• You must press this key combination before the gray screen appears.

• Now, hold the keys down until the computer restarts and you hear the start up sound for the third time.
• Release the keys and allow the Macbook to start up.
Run the next procedure (below) from within your Mac OS X Desktop.
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font.f1 {font: 13.0px Myriad Pro} Procedure # 2

-RUN DISK UTILITY -

Go to Finder Menu bar
• Click Go > Utilities > Disk Utility and open up Disk Utility app.
• Click on Macintosh HD volume (or on the name you have changed this volume to.)
• Select "Repair Disk Permissions"
**Let Disk Utility run this repair permissions until completion

Once Disk Utility is complete and there are no errors in red in the completion summary, quit Disk Utility.

Proceed to the last procedure.
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Procedure #3:
Check this Apple support page for Macbooks and make sure your Macbook is update on its firmware and SMC updates:
Apple Macbook Support page
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•Now try a few types of DVDs, commercial, burned and blank DVDs and if you have different brands of blank DVDs make sure to try them as well.
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Apple has done it best, by providing a great support page, that I would like to provide you as a final troubleshooting support option:

Apple Support Link:
Troubleshooting the slot load optical disc drive
You have your work cut out for you, but not to worry, follow these procedures listed in this post and in the links I have provided and you will have an answer as to if the issue with the DVDs auto-eject from your Macbook, is a hardware, software or DVD disc issue.

Regards,

-Mactechtrainer