Windows 7 compressing doesn't reduce space

Question

I used the compression method by windows 7 from the properties of a file but it doesn't seem to work. The folder that was around 42,6 Gb is now 42,5 Gb which means it only saved me 100 MB? Is there any other way to compress the files that i don't use (but i still want to keep)?

Answer 1

I don't know what kind of algorithm Windows uses to compress filesystems, but it just could be that your data can't be easily compressed (mp3s, compressed video etc.)

You can try to pack the data into a .7z archive with 7-zip. It uses a quite efficient compression algorithm.