[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.

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

  1. hehe..thanks man…saved me a ton of hours figuring out how to make it work..the trick worked after few tries…

      1. Can’t believe this works!! Smoke-free. Thought it was compatibility issue of my SD card and almost wanted to buy the Transcend Jet Drive to expand my HDD space.

  2. Thanks so much! worked on the first try.. after years of doing it on the pc.. and i’m a smoker indeed.

  3. I had the same problem and couldn’t get the “slide lock switch halfway” trick to work. I am trying to update the firmware on my ICOM 7300 Amateur radio and the only way to do it is through an SD card formatted on the ICOM. But trying to copy the firmware file to the SD card failed on my 2011 MBP.

    Finally just hooked up my Nikon D80 to a USB port, inserted the SD card which then mounted on the Desktop and copied the file over that way. Something worng with the SD card reader on the MBP

  4. Didn’t work for me, I had the same issue on an iMac & macbook pro, tried the tape, tinfoil and mid-position tricks to no avail. I used a led light to see inside the slot and it was all in fact just pins. a pin is pushed when the card slider is in “lock” position preventing the OS from writing. I used tweezers to scrub inside the lock recess in the iMac slot, plugged the SD afterwards and it worked. might have been jammed with dirt and dust.

  5. Unbelievable !!! It works !!! I was looking for answers for two days! Thank you so much !
    I don’t smoke

  6. Ok, that’s one of the weirder Mac fixes I have ever come across. But in my case, it totally worked! I live in a very dust free and clean environment so I’m not sure why this might have become an increasingly common problem. Anyway, thanks a lot!

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