Reasons why a computer might not be able to read an SD card?

[Bohandas]

This is unrelated to my other issue.

I've got a 32gb micro SD card from a reputable source (Microcenter) that worked in my computer before and seems* to work in my cheap offbrand smartwatch. Recently I tried to slot it into my computer (which runs Windows 10) to get my photos off of it and the computer glitches out when I try to access it. The computer detects the drive and it doesn't pop up the "there's a problem with drive [letter]; scan and fix it" message, but when I try to either access the drive or go into the drive's right-click menu windows explorer either locks up or crashes. I've already tried taking the card out and putting it back in, rebooting the computer, and switching out the card's microSD to SD adapter and none of these has worked.

Any ideas?

*It says it's saving things, and all my oldest files are intact, but the watch's onboard file explorer is so crappy and the card has so many files on it that for all I know all of the newest files could be corrupt and I wouldn't be able to tell because I don't have the patience to scroll down that far by hand; I only access the photos and voice notes that I record with the watch when I swap the card into my computer, which I've neglected doing for several months

[Manga Shoggoth]

Has the card been encrypted? The one in my tablet is encrypted, and I had many warning that it would only work with the tablet if it was encrypted (so couldn't be used to transfer files to a computer).

[veti]

In my limited experience, plugin storage devices are extraordinarily hard to troubleshoot when they go wrong - which they nearly always do, sooner or later.

Does your computer handle other SD cards correctly (as of now - experience from months ago is not reliable)? If not, that suggests a hardware (probably) fault with the card reader. Could be as simple as dust or grease on the contacts. Or a software issue - is your device driver up to date?

Can you get another reader? Consider getting a separate USB device to connect the card to the computer. That would allow you to rule out the card reader as the source of the error.

Can your smartwatch still read and write to the card correctly? If not, then the problem is presumably with the card itself. Could be greasy contacts, again, or it could be something more serious - like, your watch and computer are trying to write to the card in completely different formats, and each interprets the other's work as corruption. Is there any documentation about how your smartwatch stores data? - does it actually say you can transfer the card directly to a Windows machine and read it?

[snowblizz]

My gut feeling here would be incompatible filesystems.

Windows 10 expect it to have a certain format, and the smartwatch uses something else.

The one time I've managed to get Windows choke on external memory like this was when I formatted a usb-stick to work as auxiliary RAM one one computer, and then tried using it as a usb in another. The latte computer didn't like that, due to the way it's formatted for use. More or less, I think there's some technical jargon involved there. But the result was that if I put the usb in anything but the original computer it would bluescreen the other one.

[Bohandas]

Could be as simple as dust or grease on the contacts. Or a software issue - is your device driver up to date?

Looking at it, the contacts on the card do appear to be dirty. Any ideas on cleaning them?


Can your smartwatch still read and write to the card correctly?\

Yes, as far as I can tell. I know it can read the old files on the drive that I checked, but I can't check the most recent files because the file explorer on the watch is so bad it would take an hour to scroll to them.

[veti]

Looking at it, the contacts on the card do appear to be dirty. Any ideas on cleaning them?

They're not supposed to need cleaning - theoretically, the slot itself is supposed to wipe them when you put it in - but if I were doing it, I'd try with isopropyl alcohol and maybe a q-tip.

If you need to clean the reader, that's harder. Anything like a q-tip would leave residue in there that would make matters worse. I can only suggest Google an answer to that.

[gbaji]

They're not supposed to need cleaning - theoretically, the slot itself is supposed to wipe them when you put it in - but if I were doing it, I'd try with isopropyl alcohol and maybe a q-tip.

If you need to clean the reader, that's harder. Anything like a q-tip would leave residue in there that would make matters worse. I can only suggest Google an answer to that.

Not sure if compressed air might work (you can buy cans of the stuff). I've used that in the past with other connector plug-ins of various types. Tends to work well for stuff like lint (that just loves to collect inside various plug "innies". Never specifically tried an SD card connection though. Don't want to break anything, so I'd recommend looking this up before trying it.

Is there were I tell my (in)famous "dead gnats are apparently at least partially conductive" story? Short of it: Don't leave a bag with a piece of fruit in it, under your desk, right next to the air intake ports of your computer.

[Bohandas]

I eventually got it to work bu plugging the card into a microSD-to-USB-A adapter. I don't know why that worked but it did. It can't have been the card reader that was the problem because it reads other cards just fine