I have googled this exception extensively, and all the discussions I've found seem to be related to file uploading and exceeding the allowed file size limit. In my case however, I am not uploading anything, it is a simple postback.
I have a gridview displaying the results of an SQL query. This works correctly and displays the data as expected. Also, on the page are a couple dropdowns used to filter the data via control parameters on the SQL data source. However, any postback created on the page cause the above exception.
I have tested the query and all the filter parameters work as expected. I have tested removing various controls and cannot determine a single cause or point of failure, as the error occurs regardless of how the postback is triggered.
Any suggestions appreciated.