Music has disappeared

Mm, could you explain a little more?

For example, have you just upgraded to Win 10 and you've lost some files? Had an update? Done something to one of your disks?

Where was your music? On what device or where on your PC's disk?

Do you have any backups?

Please tell us what happened step by step from having your music to when you realised your music had gone.

You said (in your 2nd thread):
I have searched for titles on 'My Stuff' & it's there in gobbledegook,

Please use explorer. Navigate to the folder where you expect your music to be.
Post one or more screenshots of what you see, showing the files and folders. (Using the icon above to the left of the video icon)

What do you believe has changed if anything?
Thanks.
rationale: we don't know if indexing has been set up appropriately so let's first check the music is present as expected

Hi, I'm only going to consider your laptop- not your Kindle Fire.
Is the problem that you simply don't know where the files are stored on your laptop?

First considering searching: Cortana's search is limited to what's been indexed. So if your music wasn't in a location which has been indexed, Cortana won't find it.

Second, considering recovering your files. At this point we're not certain if they've been deleted, and don't even know where they should be. (path=?, folder=?, drive=?). If they have been deleted, a basic point is this: they will probably be recoverable if they haven't been overwritten by using your PC, installing programs, creating files....

If you believe they have been deleted, you can use a program like Recuva (free) to scan and list deleted items.
Use the portable version to save installing it and possibly overwriting your files.

Third, finding your music (assuming it's not been deleted).
Do you know where they should be on your laptop?
For example I have 80Gb or more (I really don't know without looking) under H:\Music
Do you know where yours should be?

Install a program called 'Everything' by void tools. (But on a disk/partition that doesn't contain your music in case it overwrites anything deleted).
Let it index everything- relatively quick.
Now you're ready to do 'Search as you type' searches everywhere.
See what you can find.