I started experiencing a problem unmounting SD card using the settings menu.
I select "Unmount SD card", the system says 'unmounting', but then it fails to unmount - i can still browse the SD card contents.
I noticed this after i started having difficulties connecting my droid to my computer via USB. In other words, when i click "Turn on USB storage", i get a spinny circle, but it never mounts. This is when i tried unmounting the SD card and it never unmounts.
Just to clarify, i can read the SD card contents just fine, if i browse through it using ASTRO, or when i plug it into an SDCard reader on my PC.