Error: "Unable to load the .Net control for this page." when trying to open a schedule or trend log in WebClient

[Product_Support]

Issue

You get an error, "Unable to load the .Net control for this page." when trying to open a schedule in WebClient.

Product Line

Andover Continuum

Environment

webClient

Cause

The problem is that the .Net zone permissions are not set on the browser machines.

Resolution

1. Depending on the revision of the WebClient the procedure for correcting this on the browsing machines is different.
   • If you are running WebClient version 1.73 or below then refer to the WebClient installation guide on setting the .Net zone permissions.
   • If you are running WebClient version 1.74 or higher, which uses .Net 2.0, the procedure is different. Below is the procedure that will need to be performed on the browser machines at the command prompt to set the .Net Zone Permissions for .Net 2.0.
     1. The following command will add FullTrust to the Internet_Zone in DotNet 2.0:
        C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\caspol.exe -m -addgroup Internet_Zone -zone InterNet FullTrust -name FullTrust
     2. The following command will add FullTrust to the Trusted_Zone in DotNet 2.0
        C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\caspol.exe -m -addgroup Trusted_Zone -zone Trusted FullTrust -name FullTrust
     3. This will result in output like:
        The operation you are performing will alter security policy. Are you sure you want to perform this operation? (yes/no)
     4. Then select Y and you should see:
        Added union code group with "-zone" membership condition to the Machine level. Success
     5. You should then be able to open the .Net 2.0 editors on your web.client browser machine.
2. In some cases adding the webclient IIS PC to the trusted sites in the browser is needed
   1. Internet Explorer> Internet Options> Security> Click Trusted Sites> Click Sites
   2. Type in http://your server name/webclient and click Add (i.e your server name is specific to your install)
   3. Deselect the checkbox for 'Require server verification (https:) for all sites in this zone
   4. Click Ok, Ok
   5. Close explorer and access webclient schedules

Note: Every browser PC that will be accessing schedules needs to have the caspol commands run on it.

Download a batch file that can be run on each PC (Rename the .txt file to .bat and run at a DOS prompt  C:\> caspolwebclient.bat)

Note: When using 1.94 SP1 check the application pools .net version selected

Name	.Net Version
ASP NET v4.0	4.0
ASP NET v4.0 Classic	4.0
Classic .NET AppPool	2.0
Default AppPool	2.0
WebClient	4.0

Note: If .net framework 4.5.x has recently been installed on browser PCs, see Webclient Cannot open .net editor with .NET Framework - 'There was an error trying to create the .NE....