How to diagnose uploads failing only on OS X clients

We recently upgrade our server to PHP 5 and file uploads are now failing, but only from OS X clients (Safari 5, Firefox 3.6) although the same browser versions on Windows work fine.

The code is failing as is_uploaded_file() is returning false when using Mac client software.

Has anyone had this error before?

Any suggestions for how I might diagnose the cause of this 开发者_JAVA技巧problem?

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How many MacOSX users are reporting this issue? Just a small portion of your mac users, or all of them? Do you have a Mac nearby to reproduce the problem? I'd be surprised if a PHP file as common as is_uploaded_file is the problem. I'd lean towards issues on the client side, or network issues. You could check the log files (if you are using apache /var/log/apache2 or /var/log/httpd) for their upload connection information or possible errors

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I have had this problem recently as well - only with safari though. I haven't had time to do a fix yet, but was going to look at what is suggested here:

safari upload woes - http://www.webmasterworld.com/macintosh_webmaster/3341383.htm

I agree that this is most not likely a php problem.