Hard drive space usage

[olvy]

I've just discovered that BTT is using 7.16GB in /library/ Applications Support on my hard disk.
In the same time the VISIBLE files only use 173.5 MB!
Ther must be invisible files in this folder.
Why?
How can I purge them?

Thank you in advance for any help.

[Caliguvara]

Try to make the invisible files visible in order to check what messes up