If this happens to you, then do the following
- Force stop on Settings, Applications, All, Media Storage.
- Clear Cache and Clear Data, for the Media Storage application
- Unmount SD card
- Take out your sd card and put it in computer
- Find the LOST.DIR folder and delete it from the card
- Put the card back into the phone
- Reboot the phone
Got this from here...
Solution 1. Clear media storage data
The simplest solution is to clear media storage database and let it restart the process from scratch. Chances are this will fix most of the issues with Mediascanner/Mediaserver. Do the following, and it should help ease-out the pain:
Settings > applications > Media Storage > clear data, force stop and reboot.
Read more: http://geeknizer.com/fix-android-media-server-scanner-sdcard-cpu-battery-drain/#ixzz4lIDijXJ7