Downloaded file from IE is locked for a while?

Question

I made a web site that converts a file into another file. The converted file is downloaded via Internet Explorer and imported to another program.

The problem is that sometimes the file can't be imported and causes an error. I guess that the file is locked for a while. It didn't happen in Windows XP. Now the OS is Windows 7.

Does Windows 7 have different file writing mechanism?

Answer 1

Is it your antivirus software? Most AV tools take any files you've just downloaded and perform and thorough scan on them before releasing them to be used by the rest of the system.