I used the procedures to load Documents, Music, Pictures and Videos to an SD card, and mount the volume so it is accessible to Libraries. At some point recently the card has 'disappeared'. I have checked it on my Desktop, and all the files are still there. When I insert or remove the card, the Surface Pro makes the right noises - so I think the drive is working OK. Somehow it is just not properly being recognised. It doesn't show up as a drive in Computer Window; nor is it visible as a Volume in Disk Manager. I used a Registry Cleaner product recently, but have reverted to the previous Registry backup; with no success. Has anybody any bright ideas...?