When you want to work with the FileUpload control in ASP.NET probably the most important thing to have in mind is that you are working with files, and files can get big, sometimes really big. By default with the FIleUpload control you can upload files that are 4096 KB (4 MB) in size.

Of course, you can override this setting by changing the httpRuntime maxRequestLegth in web.config file of machine.config file (if you wan’t to override the setting on the whole computer for every application etc.). For example:


   <httpRuntime maxRequestLength=”2097151″ enable=”true” />


(remember that the size is in kilobytes, so this is sround 2GB)

Now, this is all fine. You change it, you test it locally and it all works fine. At least that’s what I did. I even hosted it on the local IIS….Untill….

I published the application to a server that had IIS7 installed on it and I started getting a 404 Error. It was very frustrating really. Then I went trough the Microsoft documentation and found out that things are different on IIS7. There’s a completely different setting called maxAllowedContentLength under requestLimits under security. Example:

<requestLimits maxAllowedContentLength=”2097151″ />

Turns out that requestLimits is far more than just limiting the size of the files. Here’s a link for those who want to dig a little deeper on the issue:


Hope this helps someone,



Posted by TheBoyan

I have been programming since I was 11 years old (Yes, I'm one of those, for real). First programming language I learned was BASIC, on a Commodore64. Then around high-school it was C and Assembly. Just before and during university days it was C++. I started doing some professional work during this period, part of the reason why I dropped out of uni in my final year. I have never stopped since then. Going through a plethora of technologies ranging from C and Assembly languages, Delphi to C++, C#, Java and so on and so forth... trough 20 (and more, who counts, does it even matter) years of software development. I have not lost even a single bit of my ambition and love for the craft from those first young days, nor the energy...I absolutely love what I do. I like to get my hands into all aspects of software development. Now-a-days I use mainly Microsoft related technologies .NET C#, with a lot of database design/management usage of SQL server, but not in any way limited to that.

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