Most of file I had download is corrupt.
I download it with IDM, and the file size is unknown.
Why is it happen??

IDM?

You have a problem with your Internet connexion (browser, provider, communication link, etc.).

Internet Download Manager


Then why when I download it at another font site it's have no problem?

Don't use a download manager. Just click the download button and if and when you have a good connection and/or a WiFi connection that is on the edge of signal break you will get a correct zip.

Remember dejapu, download problems are 99.99% on the user side.