Overlay Icons disappear– (TortoiseSVN,Dropbox,SkyDrive,Google Drive…)

1. Regedit > KEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\explorer\ShellIconOverlayIdentifiers)
2. Rename the entries under ShellIconOverlayIdentifiers to reorder the Icons.
3. End task explorer.exe and restart it. (As same as restart computer.)

Reference: http://stackoverflow.com/questions/1057734/tortoisesvn-icons-not-showing-up-under-windows-7