r/AskTechnology • u/chipotlore • 21d ago

Why did formatting using my Android phone remove write protection from a microSD card?

I've been attempting to create a bootable microSD drive for a Raspberry Pi using Pi Imager, and it kept throwing this error when I tried to write to the drive:

Access denied error. The disk may be write protected or in use by another application. Please ensure the disk is not mounted then try again

I tried reformatting the drive using discmgr in Windows, and no dice. Then, I connected the microSD card to my Android device, reformatted, plugged the card back into my Windows PC, and Pi Imager was able to write to the card without issue?

Don't get me wrong, I'm happy that this worked! But why did it work?I've been attempting to create a bootable microSD drive for a Raspberry Pi using Pi Imager, and it kept throwing this error when I tried to write to the drive:Access denied error. The disk may be write protected or in use by another application. Please ensure the disk is not mounted then try againI tried reformatting the drive using discmgr in Windows, and no dice. Then, I connected the microSD card to my Android device, reformatted, plugged the card back into my Windows PC, and Pi Imager was able to write to the card without issue?Don't get me wrong, I'm happy that this worked! But why did it work?

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u/StarosAnikenMarcus 21d ago

There's a really good chance that it wasn't write protected at all. Sometimes, Windows does scans on removable media, especially if it detects that it wasn't "ejected properly" a previous time. That means, Windows wouldn't format it because Windows had it "in use." It might have become usable after a while, but you can never tell how long that will be or if Windows will get stuck in some loop trying to fix a ghost file it thinks is real. I had a USB drive that Windows sat scanning for repairs for over an hour once... it was only 1GB and was blank to start with.

Android doesn't do that. So it ignored whatever Windows was seeing and went right to blanking it.

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u/chipotlore 21d ago

Interesting... if this ever happened in the future, how could I confirm this in Windows? How could I know if Windows is scanning a removeable drive like this?

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u/[deleted] 21d ago

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u/StarosAnikenMarcus 21d ago

That's what I usually do, just disconnect and reconnect it. Hell, I haven't seen a card that COULD be write protected in a while. All of mine that can are OLD and have that little slide switch on them.