Unidentified Music files in internal phone memory which when deleted, - Microsoft Community

i have lumia 640 xl lte windows 10.

i store music files on 16 gb sd card save space in 8 gb internal phone memory. , store apps, music, pictures, videos, downloads in sd card , save location has been set sd card.

recently copied 3 gb of music in sd card , while looking around storage app, realized internal memory of phone has decreased alarmingly, leaving around 800 mb space left 7.28 gb.

i cannot pinpoint whether space being taken under "system & reserved" (3.47 gb) or "apps & games" (2.08 gb) because 2 space occupying categories. 

however after connecting phone via usb cord computer portable device, looked phone memory found of folder empty under "music" there 4 hidden folders: "album", "artist", "playlist" & "podcast". both "album" & "artist"  folders have music files same music files in sd card, no identification markers type of file given "file" , size of folders given 0 bytes containing 70+ files.

i tried deleting them of them deleted, receiving error messages on various files cannot deleted saying

"************ not deleted. device has either stopped working or has been disconnected" "skip", "skip all" & "cancel" option.

however, files, deleted, deleted sd card causing problem of loss of data.

i dont what's happening.

this hasn't happened before. how rid of these unnecessary files phone memory without affecting music files in sd card?

please help.

hi rahul,

to assist concern, please answer following questions:

• which os build installed on phone? check, go settings > system > about > more info.
• have made changes in settings prior issue?

we're looking forward response.

Mobile Devices / Microsoft Lumia and Nokia Lumia