Every now and again I hear a noise similar to the one you get when you unplug a USB device. Then, a second or so later, there's a similar noise and a File Manager window opens showing the D drive, which is a 128 GB Sandisk Extreme micro-SD card. It's as if the Surface Pro lost the card for a second then found it again.
When this happened just now, I also got a pop-up dialog saying, "We're unable to find the OneDrive folder because the drive is unavailable". The OneDrive folder is on the card but the OneDrive icon isn't in the system tray. I'm guessing that my OneDrive isn't being synced.
The Surface is running Windows 10 version 1511, build 10586.318 and it's the i7 8GB 128GB version. If I start an error check on the drive, I get the message "You don't need to scan this drive", so it looks as if the card is OK.
Could this be a power management issue, or something else?