Unable to format MicroSD card on 640 XL and 2 different laptops


New member
Jun 1, 2016
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I am the owner of a Lumia 640 XL on the most recent Windows 10 Mobile build (not Insider) with a 64 GB Sandisk microSD card inside. I have had this particular SD card ever since I got the phone around a year ago, and it gave me no troubles. However, recently.... I've been running into odd problems.

1. It's been difficult to install new apps or update any apps that are on the microSD card. If I use the "Storage" app and install new apps to the phone, it works fine. But to the SD, not so much - it keeps showing an error and will try to continually re-download and re-install the device unless I force the installation to stop by pressing the X.

2. I can't seem to save any videos to the microSD card appropriately. BUT it saves photos just fine (how strange?). Videos will save to the card as a file name, and will indeed take up space - but if I try to play them, they won't work (as if it's corrupted).

3. Lastly - and this is the most frustrating part - I simply CANNOT seem to format the microSD card. I own a Lenovo laptop and a Surface Pro 4. I have tried formatting through each of those laptops via the Windows explorer formatting function in drive management and I keep getting an error that it cannot be formatted. I cannot even seem to delete files from the SD card itself. My friend has a Lumia 950, and we tried putting the microSD into his phone to see if it could format - and that didn't work either. Is there any program I can use to force format this microSD safely?

Please help!


New member
Jan 12, 2015
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Card is probably broken. Every nand based storage solutions have a limited write/erase cycle life , including micro SD cards.
I recommend RMA the card , there is no way to completely repair this card


New member
Nov 3, 2016
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I think you cannot erase the SanDisk sd card on a phone, through pc. I tried it. And you cannot erase using the secured SanDisk adapter. Try it with your phone.

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