Device not seeing data on SD card

Up until now, I have been creating my waypoints and routes on my PC within Basecamp and copying them to the "User Data" folder on the memory card with the device connected to my PC via USB.

Today, the PC sees the items on the SD card, and the device sees the map on the SD but does not list any of the routes or favourites (waypoints) which i have copied to it. This is frustrating as I am unable to access the route I had planned for tomorrow! The only routes I see are those created on the device and the only Favourites are those that have ended up on the Internal Storage.

Update: Having written this problem up, I tried a few things. Rebooting the phone had no effect. I tried removing the card and putting it back in. No effect. But I deleted all the content (route and waypoints) from the User Data and deleted the remaining waypoints and routes on internal memory using the device's "delete", then copied the stuff back onto the SD card, and voila, it was all seen by the device once it had been rebooted again.

I am not sure what did solve the problem but thought it worth posting this, even though it's not a current problem for me, just in case!.