I'm using Windows 7 but I can't see why the basic way the Windows Explorer works should be any different in Windows 10.
For example, if I examine a folder within 'Music' I see this
http://www.upl.co/uploads/Music11574800770.jpg
Simply clicking on 'Name' reverses the alphabetical order, so that I see this
http://www.upl.co/uploads/Music21574800831.jpg
If 'Unspecified' is a folder within 'Music', double-click on it to open it.
Then press Ctrl and A together to select everything in it.
Then press Ctrl and C together to copy everything that you've just selected into your clipboard.
Return to the previous view (where you're looking at 'Music') and click somewhere in the window to place your cursor in it.
Then click Ctrl and V together. That will paste the contents of your clipboard into the 'Music' folder.
You've now got TWO copies of all of the relevant music tracks, with one copy being in the 'Music' folder and another one within the 'Unspecified' subfolder, so you can now right-click on 'Unspecified' and select 'Delete' to get rid of the unwanted duplicates.