1. Connect your 5800 to you PC in Mass Storage Mode

2. On your PC you will need to have allowed to "Show" hidden files, do this from Explorer/Tools/ Folder Options/ View and select "Show hidden files and Folder"

3. Open your SD memory card/Removable Disk in My Computer on PC

4. Go to E:\ Private there you will see 3 folders 101f8857, 101ffca9 and 10281e17 .

5. Go to Private\101f8857\Cache\E there you will see .dat files. Delete all the .dat file BUT NOT the E Folder. Shown above right

6. Now go to Private\101ffca9 there you will see another .dat file, Delete the dat file NOT the folder.

7. Finally go to Private\10281e17 There you should see 4 files 2 are Mp3 files other are Podcast files.
    Delete mpxv2_2.db & mpxv2_2.db-journal for Mp3 files list and Delete pcv6_1.db & pcv6_1.db-journal for Podcast files list.

8. Close all windows and disconnect your Phone. Go to Music Library and it should automatically start a refresh.

i always encounter music files missing from my memory card. is this method can solve the problem that i faced? any suggestion to prevent my music files keep on missing? i really fed up with this situation even though i dint remove the memory card from the phone.