Micro SD Card shows read only and all format/erase options are greyed out

[dingdingdang]

I'm using Yosemite on a mid-2014 MacBook Pro. I just got a 128GB Lexar Micro SD card and used on my Samsung Note 4 phone. I transferred the files to my Mac, ever since, the card becomes 'read-ogly', I can't write on or delete files, my phone can't mount the card anymore. I still can see it's in ExFAT format. And in Disk Utility, all options are grayed out so I can't reformat the card.
I tried the sudo diskutil command in terminal, it says can't do it.
I also tried the format on a Windows machine, it says not permitted.
And oh, these small cards don't have the lock flip mechanism on it.
What am I missing here?
Please help.
Thank you

 

[Rod]

When you say the operation is not permitted does it say why? If it is a permissions issue and it becomes visible in the Finder window when inserted in your MBP then Right Click it and go to Get Info.
Down the bottom you will see Sharing and Permissions. If the permissions state "read only" unlock (bottom right) and change to Read and Write.

 

[ferrarr]

I had this same thing happen with a PNY 128gb thumb drive a few years ago. Unfortunately it was out of warranty, take it back, if you can. I tried for 2 years trying to get it useable again. I tried Windows XP, Win 7, Win 8.1 and OS X Mavericks and Yosemite. I even tried a Linux live CD in one of the Windows machines and tired Hiren's boot cd. All to no avail, kept getting not permitted or can not format. I had only had about 30gb of data on it and I was able to get the data off, but the error was never resolved.

 

[badshoehabit]

Misread post and imagined it had a lock slider.

 

[chscag]

This is why we constantly warn folks not to rely on any kind of SD card with their data. Even the best ones are unreliable and subject to failure without warning.

 

[dingdingdang]

Thank you all. No there is no unlock scheme on micro ad card.
Ferrarr Bob: how did you get the data erased finally?
Thank you

 

[ferrarr]

I didn't, I destroyed it with a hammer.

 

[dingdingdang]

Bob:"...I had only had about 30gb of data on it and I was able to get the data off, but the error was never resolved."

 

[dingdingdang]

Anybody knows the equivalent command for read only or write protect in Linux? Can we change it like how to change the value to 0 in Windows?

 

[ferrarr]

Bob:"...I had only had about 30gb of data on it and I was able to get the data off, but the error was never resolved."

It was "Read Only", I was never able to write to it any more, and I didn't need the files anymore, so I destroyed it.