In some cases, I receive a critical error in SBS Console from SharePoint services. When I look into Event viewer, I find an error with this text:
The SharePoint Health Analyzer detected an error. Web.config file has incorrect settings for the requestFiltering element.
The requestFiltering element in web.config must have the allowDoubleEncoding attribute set to true in order to support file names with the + character in them.
Also, it must have a child requestLimits element with the maxAllowedContentLength attribute set to 2147483647 to avoid interfering with file uploads.
Ensure the requestFiltering element exists in web.config, that its allowDoubleEncoding attribute is set to true, that it has a child requestLimits element,
and that its maxAllowedContentLength is set to 2147483647.
For more information about this rule, see “http://go.microsoft.com/fwlink/?LinkID=163442“.
This is strange, because the element allowDubleEncoding does not exist, so I investigated how to solve it. The only think that was different in my web.config file and in the error was the value of the parameter maxAllowedContentLength. Therefore, there is the solution of the problem. Everything will be all OK, after you change this value.
You can change this value directly in web.config or true Internet Information Services. To change it true IIS, you must first download an IIS Administration Pack from here.
1. Open the IIS, navigate to SBS SharePoint site, and click on Configuration Editor.
There you have to navigate to System.webserver > Security > requestFiltering.
Apply the changes, close IIS and restart IIS from command prompt with IISReset /restart.
After this, the critical alert in the console will disappear.