Is there a reason why IE fails when download a file with no extension or .dat as the extension?

I have a basic website on one of our servers and I've created a secure directory that we can put files in and send customers links in order to download them. But, if the file has no extension or .dat as the extension it fails. If I rename it with a .zip extension it works just fine. I've unchecked the 3rd party extensions option under IE settings, any other suggestions?

Is there a reason why IE fails when download a file with no extension or .dat as the extension?violin

Yes. because then IE considers it with a system file or a virus. so oftenly IE looses the file.

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