Member Avatar for Member #1091071

I'm having a bit of trouble here.
This could be hardware related (as i'm using a new microsd to sd adapter), but I'm not sure.

So, I installed rasbpian on a microSD card a while back (a few weeks), and now i'm finished with it.
I'm trying to completely reformat it for use on my phone. I can't use my phone to format it because it only detects the first partition, the recovery partition, which is about 800MB.

So, i've got an SD card reader, and a MicroSD to SD adapter which is currently plugged into my PC.

The SD card appears on my devices list (), but no volume information is avaliable, and I can't access the card at all ().

I can't manage the device via command prompt or windows device manager either, although in the device manager it does provide correct information about the size of the disk.

I'm using kaspersky antivirus.

Before you ask: yes, the lock switch on the card is in the off position.

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  • Latest Post Latest Post by rubberman

Dani AI

Generated

Quick diagnosis and a small checklist that fills gaps in the replies so far.

Given you installed Raspbian, the card most likely contains a small FAT boot/recovery partition plus Linux (ext4) partitions. Windows and many phones only see FAT/exFAT, so the rest will appear missing even though the physical disk is present — which matches your “device shows size but no volume” symptom. That makes a partition-table/filesystem mismatch the most likely cause, but it can also be a bad adapter, a counterfeit/failing card, or the card controller switching to read‑only due to wear.

Practical next checks (in order):

  • Try a different microSD adapter and a different card reader/PC or phone. Faulty adapters/readers are very common and easy to rule out.
  • Use Windows Disk Management (not Device Manager) to see whether the disk reports full capacity or just ~800MB; full capacity but only one tiny partition points to a non-Windows partition layout, whereas the device reporting only 800MB suggests a lower‑level problem.
  • Temporarily disable Kaspersky and retry, just to eliminate AV interference.
  • If data must be recovered, mount the card on a Linux/macOS system (they can read ext4) and copy files before wiping.

If reuse is the goal (no data needed):

  • Remove all partitions and create a single FAT32/exFAT partition (do this from macOS or Linux if Windows tools refuse). If utilities refuse because the card is “unusable” or becomes read‑only, the controller has likely failed and replacement is the practical option.
  • If capacity looks wrong or behavior is flaky, suspect a counterfeit or failing card and test/replace accordingly.

Notes on earlier suggestions: ’s drive‑letter point explains Windows visibility limits; ’s formatter idea is reasonable but the official vendor/SD‑association tools or a different OS can be more reliable; is correct that a Linux environment will reveal and remove non‑Windows partitions. If after these checks the card stays “unusable,” it’s most likely a hardware/controller failure — time for a replacement.

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Member Avatar for Slavi

It seems like that your SD card hasn't been assigned a letter. You' ll have to do it manually in the device manager (say you want to assign it 'f' but I think windows requires you to use unused character). Another option would be to get liveusb of ubuntu or similiar and format your sdcard using gparted from within ubuntu

Member Avatar for Member #1091071

Ok.
Reassigning the drive letter didn't work, and neither did the SD formatter.

With the SD formatter, it says 'this drive is not supported', and through diskpart the card is listed as 'unusable'

Member Avatar for rubberman

Boot a live linux CD/DVD/USB drive and you can reformat/erase the device without any problem. To erase the drive completely, use the command (assume the SD card is /dev/sdb) "dd if=/dev/zero of=/dev/sdb bs=1M". That will happily zero out the entire device, in 1MB increments. Of course, it is easier to just erase the boot sector and partition table with the command "dd if=/dev/zero of=/dev/sdb count=1". That would take about 0 seconds... And will not force the TRIM service to wear level the rest of the drive, which is a BIG issue for SD cards and USB thumb drives.

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