Surface Pro microSD card unmounts after waking up from sleep

I finally solved this problem by enabled write-caching for the SD card.  My card no longer unmounts unexpectedly when changing power modes.  I realize this comes with some risk of possible data loss if the card is not ejected properly.

1. I right-clicked on the SD card device in device manager under Disk Drives.
2. Then clicked properties
3. Then went to the policies tab
4. And then selected "best performance"

So far, no unexpected dismounts and no data corruption.  This has also improved the performance of the device as reads and writes of large files seem to be much smoother now.

My theory is that this setting is preventing the slot from powering down while in a hibernated or suspended state.

Hello Ted

Check out my other post here

http://answers.microsoft.com/en-us/surface/forum/surfpro2-surfdevice/micro-sd-slot-no-longer-recognized-in-the-surface/2705d99f-440a-41a4-9bdf-965f1b092efd

Eventually I changed the card same make/ model, formatted it as NTFS and so far have had no issues at all...........and its been almost 2 months now.

I think Scandisk have issues with quality control ?

Try a full format on NTFS , it does take sometime

If it still has issues after that I would use the card in your phone or something else and by another one brand new for the slate.

It worked for me.

I guess we will get the same issues when the 128GB MSD card comes out!

Good luck

Simply change the driver to generic USB mass storage.