Hi, I'm new to php, learning as I go. I'm trying to write a simple file checking function to verify that an uploaded file is a zip file. It works fine for Mac users but not for Windows users. I have no idea why this is happening. Here's a piece of my code: if($img_type == "application/zip"){ // COPY FILE TO DIRECTORY copy($img_data, $path . $new_image_name); After much frustration, I changed the first line to this: if("1"){ ... and then everything else works as it should. The file gets moved to the right directory, etc. For some reason it's not recognizing zip files created on Windows machines, at least not with the code I'm using. Any ideas? Thanks!