TTom
Posts: 3
Joined: Sat Apr 09, 2016 11:31 am

Format SD Card

Sat Apr 09, 2016 11:47 am

Hello guys,

Some time ago I bought Raspberry PI 3, I bought also a SD Card (Transcend Premium 400x 32GB MicroSDHC), using installation guide for Mac OS I put there Raspbian Jessie. Everything was fine, I booted successfully Raspbian but OS seems to be in read only mode, anyway right now I would like to format that card which I used to install Raspbian on it. Unfortunately, I can not do it, all the time I get message like: "This card is read-only" or "This card is write protected".
Some of my friends recommended me to use SD Formatter which I used, but with no success (see screenshot below).
Image
Basically I tried different MicroSD adapters, I tried to format this card using Mac OS, Linux, Windows.
I will really appreciate any kind of help, I'm struggling with this card for couple of days already.

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mahjongg
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Re: Format SD Card (Car)

Sat Apr 09, 2016 2:41 pm

write protect is a very simple mechanism, where the presence of absence of a small bit of plastic opens or closes a switch, which some systems (but not any PI) will detect in software.
a micro-SD-Card doesn't have the mechanism, but its adapter will.
Its possible the card reader of your PC has a fault, or you might simply have the card(holder) write protect slide in the locked position.

p.s. if the card was used before you MUST use the official SD-Card formatter, and you MUST use the two possible switches in the software (non quick format and the other one) plus it recommended to enter a label name. otherwise the various partitions on the card are not removed, and only the first small partition is actually formatted.

TTom
Posts: 3
Joined: Sat Apr 09, 2016 11:31 am

Re: Format SD Card

Tue Apr 12, 2016 2:32 pm

Unfortunately, no - it looks like a different problem.
I know about lock/unlock switch or broken card reader etc and definitely all it's ok.
Anyway I tried it with:
  • 7 different laptops (2xMac, 2xLinux, 3xWindows)
  • 3 different card adapters (All of the adapters are working fine with other microsd cards)
  • Using SD-Formatter, builded in apps, command line
And all the time it says card is read only, any clue?

fruit-uk
Posts: 609
Joined: Wed Aug 06, 2014 4:19 pm
Location: Suffolk, UK

Tue Apr 12, 2016 2:39 pm

TTom wrote:And all the time it says card is read only, any clue?
Almost certainly dead/fake. Some will report as read only in that state

TTom
Posts: 3
Joined: Sat Apr 09, 2016 11:31 am

Re: Format SD Card

Tue Apr 12, 2016 7:32 pm

What do you mean by saying fake?

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kusti8
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Location: USA

Re: Format SD Card

Tue Apr 12, 2016 7:35 pm

TTom wrote:What do you mean by saying fake?
Where did you buy it? Some sellers sell fake SD cards in that they really have very little memory or are defective. With my Mac I had to tape the write switch the correct way on my adapters because it was switching it to read only as soon as I put it into the slot.
There are 10 types of people: those who understand binary and those who don't.

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