MicroSD card randomly unmounts itself

Question

I inserted a Samsung EVo 128GB micros-SD card into my new Surface 3, intending to use it as photo storage for my photography workflow.

However, after a fee minutes - even without using it - the drive appears to unmounts itself. It's still visible in Explorer, but clicking it results in Explorer hanging and eventually giving the error "please insert a disk" after several minutes. In Disk Manager, the drive sometimes appears, with the correct amount of space, but indicates it's all unallocated.

This issue is fixed temporarily by removing and reinserting the disk, but a short time later it unmounts itself again. I tried the disk in my older Dell Venue 8 Pro, but the issue didn't occur there.

I've looked at previous threads about similar issues on older and Pro models, and tried setting the policy for the microSD drive to 'better performance' and even tried setting up a VHD, but none of these provided a solution.

Does anyone know what I can do?

Answer 1

Some people have fixed "worked around" this by formatted the card with exFAT. I had two SanDisk cards and this helped them. 

I have a PNY that has worked fine so far with the NTFS file system.

Answer 2

Same issue.

I tried 3 different SD cards:

  1 Toshiba C10  32G FAT32

  2 Samsung (Orange) 64G FAT32

  3 Transcend x300 64G exFAT 

Didn't see un-mount issues on 1 and 2.

Serious (continuing auto un-mount for 3 or 4 times) problems on 3.

But 3 has been used on my Venue 8 Pro with no problems for 1.5 years.

I don't want to format the SD card into FAT32. Really don't want.

Answer 3

I had similar problem, try this:

My Windows is in Chinese, so my instruction may not be of the same words appearing on your system, you might have to guess a bit

go to "device manager", right click the drive under "disk drives" (not the disk controller where the code 43 error shows), click properties, click "policy", the second tab on top, then you wanna select the lower option "better performance". Save your changes. 

I have not have random un-mount problem since I made the changes, just remember to use "safely eject" function on your task bar every time you try to remove your SD card from now on.

Answer 4

I've just got my new Surface 3 followed by a 128GB microSDXC card (Lexar, Class 10, x633, 95MB/s). As with many people here and other sites I've read about, I am also having a problem with the card unmounting itself randomly as well as after sleep.  I've tried numerous tips people are talking about for this problem, but none of them worked.

I am now in the process of sending it back to the seller for refund, and getting a new one. I wonder if anyone has successful experience with using a large-capacity (128 or 64GB) microSD card on Surface 3 without any problem? I'd love to know the particular brands, models and capacities.

Cheers!

Answer 5

Several folks have had good reports about Samsung branded ones.