EDIT 25/1/15: I should add that shortly after “resolving” the issue, the micro SD card has completely failed. Whether this was a cause, an effect, or a coincidence I couldn’t say. Since I barely used the SD card in the tablet anyway I won’t be replacing it.
I have an LG G-pad 8.3 Android tablet. It’s a very nice device. But recently it kept telling me that the SD card had been removed unexpectedly (it hadn’t) and that data loss may occur (it didn’t).
After scoping out the usual Android forums I found a couple of suggestions. The one that appeared to have been most successful was a complete reset of the tablet. Another reason I chose this was because a few people had mentioned that the problem started after using Link2SD, a program designed to move apps to the SD card which doesn’t work with KitKat because it can’t override the restrictions on external storage (not that the developers bother to tell you that).
Anyway, I took the bold step of resetting the tablet, putting my faith in the LG backup software to remember my settings. It was only a partial success. Although all my apps were downloaded automatically, the user accounts I had set up for my family were completely lost, including their progress through games. And the SD problem remained…
Frustrated by my hastiness to reset, I searched for another solution. A very simple one cropped up. Simply putting the SD card in another device seems to rewrite a register on the card, solving the problem. So, I put it in my Windows Phone, asked to save media to it by default, took it back out again, and put it in the LG tablet. There were a few extra empty folders on the card (used by the phone to store pictures and music), so I deleted them. The most important thing is that the problem was solved!
Hope this helps if you are suffering from the same problem.