Nikon D90 E message in display window

[peterbj7]

I keep one of the very useful USB+ SD memory cards on my keyring, and a while ago I went wading in the sea forgetting it was there. It was completely submerged for maybe 30 minutes, and it was another 30 minutes before I could get to any fresh water. I washed it off with detergent and warm water, dried it, and popped it into my computer. Worked perfectly, the files were still there, and it still worked six months later. But pulling it out of a computer without clearing the buffer first could easily destroy it.