What is using so much memory?

[cityten]

Hello,
I have a Samsung Galaxy S6 running Android 7.
I have a bit of a mystery. I'm wondering what is eating so much memory?
I am currently showing that I am using 29GB but not sure how I got to that number.
My music is taking about 15GB. Images are approx 500MB and I am at close to nil on videos, documents, downloads and installation files.
If I go to My Files > Internal Storage with hidden files enabled and select 'all folders' then 'details' the size is about 16GB. So, 13GB is unaccounted for.
I added up all my apps and those are running about 4GB.
So, what's eating all this memory? What is causing it to add up to 29GB?
If anyone knows what is going on here please let me know.

 

[chanchan05]

You didn't mention the app cache and additional app data that isn't counted in apps.

 

[cityten]

Okay, thanks for the response. Your answer is a little over my head, but I guess my question now is:
Is this memory I have to live with, or could I realistically delete or back up this data?

 

[Rukbat]

You can back up any of your files (to a PC, a cloud account or - best - to both), then delete them from the phone, but you'd have to delete a lot of them to gain any appreciable amount of storage, unless you have a few large videos.

Also, when you're in Settings/General/Storage, tap Cache and let it clear the cache. (You won't lose any data - that stuff is supposed to be cleaned up by apps when you close them, but if you use the Home button when you're finished with an app, it never closes, so it never gets the chance.)

 

[cityten]

Okay Thanks Rukbat!