HTC One Mini Storage Problem - apps taking up more space than actually installed!

[blandphone]

I am having an issue with storage on my HTC one mini. I am at nearly 90% storage but am not sure how!
When I use clean master it tells me I have 8ish-gb of space marked as other, however when I check internal storage under settings it is showing as 8.5gb of apps and just the usual 4gb of other (which I know is the operating system etc). But when I use the wizard to try and clear space, apps only add up to about 800MB. I have about 1gb each of music and pictures so what the hell is taking up about 7gbs of space on my phone?? Any help/tips appreciated. Pictures attached to show storage space.

 

[B. Diddy]

Welcome to Android Central! According to this article, the One Mini actually only has 10.44 GB of usable Internal Storage, after accounting for the OS, Sense UI, and bloatware. How Much Space Does Your 16GB Phone Actually Have? | TechnoBuffalo. So that means 5.5 GB are taken up by the OS and bloat.

A lot of that app space that you see may be due to preinstalled HTC apps that aren't considered system apps, and can't be uninstalled either.