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How to Resolve sense key = MEDIUM ERROR on MacBook Pro April 8, 2008

Posted by asimag in MacBook Pro, OS X Leopard.

Update: July 2009

I have moved this Blog to new Address:

Please post comments on new Blog. I will disable further comments on this blog.

Thank you


After 9 months of purchasing my MacBook Pro I was faced with Error while burning my CDs. Toast reported sense keyMEDIUM ERROR and eject CD. I google the error and was surprised to see so many users are having this error. Some were blaming to cheap CDs while others recommended to repair permissions or re-install OS.

I continue to face error on some cds while some burn fine. I concluded that it may be defective cds but when I used same cd on my external writer they burn fine. On 12 months my burner finally gave up and now it was not burning any type of CD/DVD.

I went to shop purchased Philips CD Cleaner which had two brushed on it. Inserted it into my dvd drive. Instructions played to choose track no. 14 for cleaning. I did as instructed and WOW my dvd burner was functional. I have burnt quite a few CD with no problem at all.



1. tbone - May 31, 2008

I’m having the same issue with my macbook pro that I purchase about 10 months ago. It’s an Intel Dual core 10.4.11 build. I’ve heard a lot of bs about this being an issue with the type of discs, or the processing speed being too slow. I have Verbatim top quality medium, along with the 2.4 Ghz processors, so it’s def. not that. I’m going to try using a disc cleaner, your post was really helpful, thanks.

2. Lincoln K. - June 3, 2008

Yes I agree , Many thanks for this obvious tip! Ive had my Mpro for 8 months and its obvious to me now that Your right the Laser just needs a Clean, and then will work fine 🙂

I will Post this around the net cheers, Many people are stumped by this error! Why Da hell dont software just say, “CLEAN HEADS PLZ”

3. Gijs van de Nieuwegiessen - July 1, 2008

Experiencing the exact same problem when burning DL DVD’s. I wasn’t able to burn Memorex, or whatever the brand is called. I’ve read lots of posts advising to use Verbatim instead.

It solved my problem back then,

Right now (2 months after burning my last DL) I’m experiencing the same errors. No problems when burning CD’s or DVD’s, but Verbatim DL DVD’s won’t burn anymore.

My last hope is cleaning the lens…

Thanks for your post.

4. Hoinowlosciplenoums - December 29, 2008

njrsukyskxuyqffhwell, hi admin adn people nice forum indeed. how’s life? hope it’s introduce branch 😉

5. Giu - February 10, 2009

You safed my “maclive” 😀 i was in trouble about that problem and a simple cleaning disc (which was since 10 Jears in my cd-board) helped like you said in your post.
Thank you!

6. DrLex - March 4, 2009

Here’s another lens cleaning success story. My drive started refusing to burn CDRs and DVDRs, and it even had problems reading burned discs. It happened quite suddenly, so I suspected that the drive was broken until I read the many successful reports of cleaning the lens.

I didn’t have a cleaning kit and I wanted to see what caused the problem, so I went a step further and took my MacBook Pro apart. I opened the drive and cleaned the lens with alcohol (well, vodka to be more exact because I didn’t have anything more pure :)) And indeed, it now burns the same discs it refused before.

Don’t bother trying the software-related tricks like changing the system language, repairing permissions or resetting the PRAM (the age-old ritual of trying to appease the Mac Gods). Just get a good cleaning kit.

I took some macro photos of the lens before and after cleaning: http://tinyurl.com/cr8z7q and http://tinyurl.com/ck8sff
As you can see, there was only a small amount of dust, but that seems to be enough to sabotage the drive. A good cleaning kit should be able to remove such tiny amount of dust, so opening the drive is overkill (but it was interesting anyway).

7. Alex Rojas - March 6, 2009


This is something that I found in VideoHelp by basskadet

Seems like it’s an Apple problem, not Toast


A Medium Error is in reference to the media used (i.e. a problem with he disk). However, there are lots of things that can go wrong with the media which is what the ‘sense code’ refers to. 0x73, 0x03 is to do with laser power calibration.

Every disk brand and type uses different power ranges for the laser and it is down to all sorts of reasons (even the dye used on the disk affects it). Therefore, every disk manufacturer incorporates a section of the disk that the drive reads before any burning takes place. That effectively calibrates the drive’s laser for the specific media being used and it does this before writing the lead-in.

Lots of people are suggesting changing the media to rectify the issue but, while this might prove successful because every disk uses different ranges of power, it isn’t really solving the problem.

This is a VERY common problem with the Matshita drives Apple choose to use and I have come across it regularly myself which is why I have looked into it. I am no great expert on the subject and am merely stating what I have so far discovered for myself.

There are lots of threads on this topic and people seem to suggest numerous solutions. However, be careful because, as I pointed out earlier, there are lots of things that can go wrong with media and that is what the sense codes are for. So what might work for one sense code does not mean it will work for another, even if they are close.

I do have a few suggestions though. the sense code 0x73 0x03 is basically down to 4 variables, the laser, the power to the laser, the thing controlling the power and the media.

So, use a media you know should work (i.e. one that always has for you in the past). Clean your laser and your drive thoroughly. Check your RAM and if there is anything fishy you should replace it. Reset the PRAM (Shut down then reboot holding Command-Option-P-R altogether until you hear the startup noise for the second time). Finally, and perhaps the most straightforward suggestion, try a different PSU/Battery. Apple power supplies can be dodgy and this has worked for external drives with the same troubles.

However, I am no expert so someone who knows more about drives might have some other ideas.



8. Felix - March 28, 2009

Thx, my macbook pro burner is now back in buisness. Really cool!

9. alex rojas - March 28, 2009

Everyone that owns a Mac should use this app: BURN.

It does everything that Toast does, and it’s FREE

And besides that, seem that the ERROR KEY thing… is not happening (at least not still)


Cheers, and Long Life MAC !

10. alexliz - April 2, 2009

Man, you rock! I had become so so so very depressed with my MacBook Pro’s optical drive (17″ August 2007): at first it stopped writing on DVD+R, then DVD-R as well. I had fiddled with Language sequences, permissions, zapping PRAM, resetting the SMC, then I tried the obvious: cleaning as per your instructions.

I went out and got the dry brush disc thingy, and, contrary to my expectations (I didn’t think anything would change), I popped the same disc that had previously failed to record and Presto!


JacobHolladay - August 3, 2012

To Minecraft

11. GP - April 6, 2009

Works wonderfully now. Thanks a bunch!

12. KT - April 20, 2009

It makes sense that it should work. Unlike other laptops, macs have an open slot that dirt can get in, whereas other laptops usually don’t. Their cd trays are some what more sealed from the environment.

P.S. I just blew some canned air into my slot, and it now works just fine.

C45p31 - January 23, 2011

This really works.

Tried on many and it works.

13. DrLex - April 20, 2009

Indeed, although there is a kind of ‘flap’ in the slot, dust can still get in quite easily. Especially when inserting a disc, dust that has gathered on the outside of the flap can get pushed inside.
So now I tape off the slot whenever I’m not using the drive for a long period. It doesn’t look too daft when using matte transparent tape…

14. UWAYEZU Olivier - May 4, 2009

Hi everyone I read yours but I think we have the same problem even I have a mac book.
when I burn a DVD it writes “burning the disc failed because an unexpected error occurred. ( Error code 0*80020064) I suspected that is caused by an incompatible CDs. so I need your help on this e-mail olivisday1@yahoo.fr

UWAYEZU Olivier - May 4, 2009

umva nkubwire ushobora kuba wanditse nabi ikiazo cyawe.

15. UWAYEZU Olivier - May 4, 2009

Hi everyone! I read yours, but I think we have the same problem even I have a macbook.
when I burn a DVD it writes “burning the disc failed because an unexpected error occurred. ( Error code 0*80020064) I suspected that is caused by an incompatible CDs I burned before. so I need your help on this e-mail olivisday1@yahoo.fr

16. Dr.Prashant k Prasad - May 16, 2009

Hii this is Dr.Prashant from India..well i read the story above mention by one of the brilliant fellow…i exactly followed what he emphasized…and the error for burning the dvd went…and its really working just go to the market and buy 6 brushed lens cleaner..follow its instruction launch it in vm ware fusion,coz its for the windows platform….after that you are ready to goo….thanks a lot…folks…god bless…thanku…

17. Dr.Prashant k Prasad - May 16, 2009

imp app are liquid cd,burn,express burn…

18. George Bonk - July 10, 2009

Not having a CD disc cleaner at hand, I tried another simple technique. 1. I squirted a liberal amount of Fairy Liquid into the CD insertion opening. 2. After gently rocking my MacBookPro back and forth I then blew a mouthful of fizzy bottled water through the CD slot using a straw. 3. Next I wrapped a bread knife with some toilet paper and jiggled the blade & toilet paper into the slot to soak up the water/detergent. 4. To finish off I used a hairdryer to blow hot air into the laptop and a long piece of wire to hook out the last bits of toilet paper. Unfortunately I am not sure if it has resolved the problem or not, as the laptop has decided not to start up again… Bloody macs!!

19. alexliz - July 11, 2009

@George Bonk(ers): You _are_ joking, aren’t you?

20. asimag - July 11, 2009

I have moved this Blog to new URL:

Please post comments on new Blog. I will disable further comments on this blog.

Thank you


21. Benny - July 19, 2009


Hey thanks. Just what I needed. Was looking for info on Sunday and came across your blog post. Don’t have time to really comment today, will come back later on. Thanks again….

22. Anthony - November 24, 2009

Can’t tell you how happy I am!!! Same problem……….the 2008 15″ Macbook Pro. Error messages, medium error……sense key = medium error……..sense code = 0 x 73, 0 x 03. Now I Know it’s gotta be a dirty lens, because this machine is 2 months old, however I have been burning my balls off! Good call, and thanks for the advice! I used a DVD with a brush built into the actual DVD. Maxell DVD lens cleaner..Everything burned right away after using once!!!!

23. crazygoat - January 9, 2010

Hey Everyone!!

The solution is a good optical cleaning!! MacBooks & MBP’s have this common issue mainly 2006 to 2008 models (really sh!ty model year of Mac DVD drives).
Buy a Optical Clearner Kit (looks like a CD with a brush on the back side).
Follow the instruction and try burning or reading your disc again.

Enjoy Everyone,

24. alexliz - January 10, 2010

Let’s have a whip-round and get something for this whiz-kid, ‘crazygoat’, who was successful in sorting out our optical drive woes!

(in case you miss the sarcasm, let me just remind everyone that this problem has been identified and solved _ages_ prior to crazygoat’s gloating comment.

Just read before you comment, you wiseguy!

25. Sgt BigK - April 29, 2010

To all who are having burning DVD issue’s. Stop using Toast. Apple and Roxio are having compatibility problems, why ? I do not Know, alex rojas is right Use a program called BURN, it works just great and it is free.

26. hluv - May 28, 2010

Brilliant! I have been dealing with this very same issue for a year now thinking it was my disc brand at first and then DVD drive failure. Searched to no avail, read countless forums, and finally i somehow stumbled onto this brilliant blog!

cheers and a hip hooray for the genius who “cracked the code!”

Went directly to the shop and picked up a Maxell Disc Lens Cleaner, and would you believe it $15.00 later I ran a cleaner which only took 20 seconds to do the job! And, for the first time in ages I have been able to burn discs again!

But, credit must be given where it is due. I thank everyone for writing their success stories in utilising the lens cleaners. As well, “crazygoat” but I think the one responsible for actually cracking the code first on this blog is Asim. The one, I believe, who moved this post from another blog.

so, here’s thanks to everyone as well as those brilliant techie brains that solved this splitting headache of a problem. saving a lot of money as one no longer needs to keep tossing out dvds after getting errors that the disc is bad or unreadable. or, swopping out the disc drive.


27. Pierre Ami - May 29, 2010

When I turned of Web Sharing and Bluetooth Sharing, Leopard burnt my CD-Rs fine with Toast. Did not have this problem in Tiger.

28. Terri - July 30, 2010


29. Christoph - March 20, 2011

Used some canned air in the drive opening. Problem solved.

30. Yer Uncle Tony - October 15, 2011

I find a really good blast with an Air Duster helps. Just insert the red tube a little and give it a blast up and down a few times. Works wonders for me!

31. William - November 14, 2011

My problem: DVD’s not burning ( + and – R) on MBP 15″ 2008. Solution: Bought a DVD Lens-Cleaner from WHSmiths (UK) for £8.99.

Burnt first time, sorted.

Jack - December 16, 2011

For me it was the media. Memorex DVD+R was no good. Memorex DVD-R was just fine. Both are supposed to be compatible with the drive, but apparently not from this vendor.

32. bruno bona - March 14, 2012

Back in business!
Thanks a lot!

33. Sensekey error | Selectdesigns - August 4, 2012

[…] How to Resolve sense key = MEDIUM ERROR on MacBook Pro …Quick overviews and basic info on Key Code Qualifier. Key Code Qualifier is a computer term used to describe an error-code returned … K – sense key – 4 bits, (byte 2 of … Latest news and videos … […]

34. mobileease - August 22, 2012

Buying a CD Cleaning Disk From WhSmiths (£6.99) sorted my issue, looking at it after it was very dusty indeed. Dry method, no liquid required. I did put some isopropanol on it though as i had some laying around.

Thank you for the advice and saving me taking my Machine Apart.

35. Jaime Figueiredo - October 12, 2012

Hey! Thanks for this very helpful tip. I had this problem with this pack of Memorex DL dvds and finally decided to google the error message to arrive at this page. I ran a laser matic lens cleaner cd and worked.

36. summer internship - May 6, 2013

Have you ever thought about publishing an e-book or guest
authoring on other blogs? I have a blog centered on the same ideas you
discuss and would really like to have you
share some stories/information. I know my subscribers would value your work.
If you’re even remotely interested, feel free to send me an e-mail.

37. Anna - June 4, 2013

I’ve searched and searched on the internet about this issue and no one seems to have a problem quite like mine. I have an iMac, the DVD drive stopped working a while ago, so I use an external DVD burner (SONY) that has worked perfectly until now. I recently changed the HD and RAM of my iMac. Everything worked fine until I tried to burn a DVD. I used Toast and the Mac OS burner and I get Hardware Error 0x03, 0x01 and also MEDIUM EROR. I tried with a different DVD burner and the same thing happens. I also cleaned the lens. I thought it had something to do with the HD and RAM recently changed but then the strangest thing happened. When I couldn’t succeed in burning on my own iMac, I used someone else’s and the same error code appeared. That’s when I even suspected a virus, that’s how lost I am. I need HELP!

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