Wednesday, 27 January 2010

ASP.NET Error: System.Web.HttpException: Maximum request length exceeded

On several applications I have developed, the users need to be able to upload binary documents (discussed in other posts).

After a while, I kept getting the error:

System.Web.HttpException: Maximum request length exceeded

Easy fix. The problem is that by default, the maximum request size is 4mb. So when a user tries to upload a file which is larger than that, an exception occurs. The resolution is to increase the maximum size of the request, so add the attribute below to web.config (you can use a maxRequestLength up to "2097151" (2 GB) for the .NET Framework 2.0):


<httpruntime maxrequestlength="10240">

This is also explained quite nicely but without much background in a Knowledge Base article on the Microsoft Support site.

Remember, if you are imposing a maximum file size for upload you should notify the user of this restriction and handle any attempt to upload a larger file, or they might see errors again.