[SOLVED] Macbook SD Card Read only solution.

And how to get read / write access to the macbook pro sd card

This workaround will explain how to solve the Macbook sd card read only

I can’t believe I’m going to write this stuff, but it is real, you believe it or not. I don’t have the category “Acrobatic Hardware Usage”, but if I had, that’s where this post should go.

If you are here, probably it’s because you are trying to mount and use an SD card (most probably an SDHC card) with your on-board Macbook Sd card reader, without success.

Pre: Please remember that there are 2 different cases which can lead to a non writable file system on the SD card by the Macbook SD Card Reader:

  1. Disk Utility will refuse to write on it, even if possible, if the SD Card contains a Master Boot Record (MBR).
  2. It cannot be written if the SD card external hardware write protection switch is wrongly detected always as it was on.

This article will cover the workaround for the situation described in the second point:

Faulty SD Card external protection switch detection by Macbook SD card reader.

Problem Description: Many SD Card used with the on-board SD card slot of my Macbook can be mounted and used as read-only file system. This is very annoying, because it means that I should use an USB Card reader to bypass the always-on writing protection detected by my Macbook SD Card Slot / Reader. Isn’t it?

Obviously I have searched all over the internet to find out a funny and simple solution to trick my mac: You just set the external write protection switch on the middle of its two usually possible positions: incredibly it will works!


This image shows the Macbook unwriteable sd card trick
This image shows the Macbook non writeable SD card trick

Now if you get it working by doing this, may I ask you to leave a comment and specify if you are a smoker? Because I suspect that this issue is caused by the airflow, which deposit dirt on the switch detection mechanism leaving it stuck in that position. The switched on plastic external switch should push it and with a non-protected SD Card, it should stay out because the switch is not in the right position to push it. If you are a smoker this will confirm more solidly my hypothesis. So please let other people know about this.

Thank you


EDIT 2015-01-11

It seems so far that the weird behaviour of the switch detection is not related with dirt or with some kind of sticky compound that the airflow transports in that area. At least this is not related with smoke, which produces one of the most sticky dust possible. 

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Author: Giuseppe Urso

Giuseppe lives in Haarlem now with his shiny dog, Filippa In 1982 received his first home computer, a Commodore 64, followed by Datasette and a 1541 Floppy Disk Drive. In 1999 he installed his first Linux distro (LRH6). In 2006 he switched to Debian as favourite OS. Giuseppe Urso actively sustains the Free Software Fundation and his founder Richard Mattew Stallman, he speaks to people trying to convince them to join the fight now, and about how important is to use Free Software only. He has a job as Infra Specialist at Hippo Enterprise Java Cms an Open Source Enterprise class Content Management System, one of the coolest company ever, in Amsterdam. He's always ready to install Debian on other people computers for free.

89 thoughts on “[SOLVED] Macbook SD Card Read only solution.”

  1. THANK YOU! As you suggested, the middle position for enabling me to format my SD card worked! No, not a smoker, and the SD card was brand new. Now I can start using my raspberry pi. Thanks again

  2. worked for me. great solution! i only use the laptop in non-smoking environments so i think this is not causing the problem.

  3. Yes, Smoker,
    Cannot believe its something so simple as putting the switch in the middle.
    SD Card lives in the Car’s Radio, don’t smoke in the car, wanted to put some new music on it, I could read but not write.

  4. worked…amazing, I work with computer 20 years, and this solution was “WTF!”. Thanks for sharing. Sharing is caring.

  5. Thank you so much for posting this tip (fwiw, i’m a non-smoker). I’ve got a Verbatim-brand 16GB SDHC card this kept tripping me up on, and i’ve found out that this card has a slight variant on this issue. If you move the Lock switch *all the way* up, it goes ‘past’ the write-enable state and becomes locked again. But if you move the switch down about 10%, with notably less force than it takes to move it to the real Lock state, it becomes writeable again. So that may be all that’s going on – maybe you just write-enabled it too much!

    1. Well it took a while to me in order to understand but, thanks to your comment, i got it. It’a a matter of very few 1/10 millimeter so, at this point it remain either constructive defects or someting related with usage, environment, chances, falls.

  6. Thanks a lot! That trick worked for me too, but I’m not a smoker, and my MBP works almost all the time in a smoke-free environment.


  7. It was dust ! After a few blows inside the card reader slot it went back to normal.
    Thanks a lot
    PS: MACBOOK PRO 15 2.7 intel i7 10.8.4

    1. After a few blows inside the card reader with the locker in the middle, now it went back to normal, incredible, thanks! I am not a smoker!!!

      1. Thank You very much. That’s the point. I blow couple times and my card reader allow me to write on SD card again.

  8. Hello,

    thanks a lot for your trick: it works great (and you save my evening, if not my night).

    BTW, I am not a smoker.

    Best wishes,

  9. For me the tab had to only be moved a tiny amount from the full LOCK position – about 10-15% back as someone previously said.

    Then the card had to not be inserted all the way into the slot, about 1mm back from fully inserted.

    This strange combination of guesswork made me feel ever so good about buying a £1600 laptop.

    1. Yes 1800 Euro laptop, but I decided this is my very last apple product. Too much fashion, too much “defectiveness by design”. Indeed Lenovo and Free Software are more than better.

  10. Well done, I had problems for a long time and my only resort was to eject it over and over again until I was able to write to it. Your method its much better!
    No smoker and brand new SDHC
    Thanks again

  11. I had the same problem with my MacBook Pro 15″ mid 2009.
    The problem is a dirty or little bend write protection tip/arm on SD card slot.
    I had disassemble the motherboard and clean the tip/arm on the side with alcohol and compressed air. Now it works! Not perfect but now I can write two out of five times I put in a SD card.

  12. This worked! amazing I can’t wait to go back to windows. I’m not joking. my mac cost far to much to fix

  13. This just saved my life. It worked in the middle position. Smoker but I normally don’t smoke where my computer is, I go outside.

  14. It was most definitely DUST. I tried switch half way, pushing sides of card, formatting various types, various cards / capacities, but low and behold — compressed air in a can saves the day again.

  15. thanks for this solution,

    i knew it must have been a hardware problem since i tried writing on the sd in both os i have on my mac mini, i do smoke but not in my room, however dust may have went in when i switched out the HDD on my mac mini a few months ago.

    thanks again

  16. Fair play. Maddest tech solution since bluetack fixed wobbly ZX81 ram-packs almost 25 years ago.

    (google it, kiddies.)

    Was smoker, now ecig, but makes lots of vapour.

    Thanks again.

    1. done, amazing.
      …The RAM pack was top-heavy and was supported only by the edge connector. It had a habit of falling out of its socket at crucial points and crashing the ZX81, losing anything that the user had typed in. Users turned to using sticky lumps of chewing gum, double-sided tape or Blu-Tack to cure what became known as the “RAM pack wobble” problem.

  17. OMG! never thought the solution is very simple. and it works!!

    i’ve tried many ways, i have MBP with bootcamp, i thought it was windows 7 bugs, tried to edit registry, etc. then when i tried in MacOSX, same thing happen, i suspect theres something wrong with hardware, coz when i open in other laptop, no problem…

    thanx for the solution.

  18. Oh my god!!!!! You are a hero!!!

    Have been fighting with this issue for so long and this works!

    You made my day!

  19. WTF?!?!?!

    Initially I thought: “No way this will work”….

    But I was so desperate, I gave it a try anyway…


    Respect and thanks!!!

  20. LOL!!! Which is exactly what I did when this trick WORKED!!! Thank you for publishing this!!
    – Non-Smoker

  21. I am a smoker but this SD card is always in my car’s cubby-hole which is a smoke free environment.. The middle setting worked on my Macbook Pro 13-inch as well! Thanks so much!

    1. Hmm I might have been not the best writer, but i was referring to the sd card slot getting dirty with dust.

      I explicitly asked people to leave a comment specifying whether or not they smoke. The reason being that the airflow in macbooks goes through the keyboard keys and comes out right below the display. I really like this solution (brilliant) because it allows you to take you mac to bed, and watch a movie without the hassle of overheating.

  22. Parabéns! Simon Harris, movi 10% a chave na outra direção e o card esta disponível para leitura e gravação. Obrigado a todos

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