Installation and Update Issues

• Feb 07, 2022
• 3 minutes to read

The links below describe how to solve installation and update issues:

• Type ‘X’ exists in both assemblies / Type ‘X’ is ambiguous in namespace ‘Y’

• Could not load file or assembly ‘X’

• Cannot modify the Global Assembly Cache

Type ‘X’ exists in both assemblies / Type ‘X’ is ambiguous in namespace ‘Y’

Error Description:

This error occurs because .NET does not allow you to reference assemblies with the same name but different versions in one project. When you try to open a page or compile an application, the framework tries to load older assemblies that are already replaced with new assemblies.

Solution:

Follow the steps below to solve this issue:

1. Close Visual Studio.

2. Use the DevExpress Temporary ASP.NET Files Clearer to clear the following “Temporary ASP.NET Files” directories (you can clear these directories manually):

   • C:\Windows\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\
   • C:\Windows\Microsoft.NET\Framework64\v2.0.50727\Temporary ASP.NET Files\
   • C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\
   • C:\Windows\Microsoft.NET\Framework64\v4.0.30319\Temporary ASP.NET Files\
   • C:\Users[your_user_name]\AppData\Local\Temp\Temporary ASP.NET Files\

3. Restart the “World Wide Web Publishing” service (Start menu\Settings\Control Panel\Administrative tools\Services).

4. Clear the project’s Bin and Obj folders and deploy new assemblies (optional).

5. Find the App_Licenses.dll file within your solution and delete it (if this file exists).

6. If you use a custom theme, use the Project Converter to update a custom theme project. Generate a new theme assembly, add it into your application, and remove the old theme assembly.

7. Rebuild your application.

8. If you use any Version Control System (for example, Git or Microsoft TFS), check whether your repository contains unused libraries and remove them from this repository.

See Also: Upgrade Notes

Could not load file or assembly ‘X’

To resolve this issue, first, try recommendations from the previous section: Type ‘X’ exists in both assemblies / Type ‘X’ is ambiguous in namespace ‘Y’ issue.

Ensure that you copied DevExpress assemblies into the web site’s Bin folder after the website is deployed on the production machine. You can use the DevExpress Assembly Deployment Tool to deploy assemblies.

See also:

• How to deploy the DevExpress controls without GAC access

• Install DevExpress Assemblies to the GAC

• Could not load file or assembly “Microsoft.Windows.Design.Extensibility” or Could not load file or assembly “DevExpress X” when you use AjaxControlToolkit

Cannot modify the Global Assembly Cache

Error Description:

This error may occur when the DevExpress installer does not have access rights to the GAC or security software (antivirus or firewall) blocks access. The installation log file can contain the following information:

09.05.2019 18:36:16 *********************[Error]*********************
Cannot modify the Global Assembly Cache for DevExpress.XtraCharts.vXX.Y.Web.dll - -2147024891
*************************************************
09.05.2019 18:36:16 --- Updating the Global Assembly Cache for DevExpress.XtraCharts.vXX.Y.Web.Design.dll
09.05.2019 18:36:16 *********************[Error]*********************
Cannot modify the Global Assembly Cache for DevExpress.XtraCharts.vXX.Y.Web.Design.dll - -2147024891
*************************************************
09.05.2019 18:36:16 --- Updating the Global Assembly Cache for DevExpress.Web.ASPxGauges.vXX.Y.dll
09.05.2019 18:36:16 *********************[Error]*********************
Cannot modify the Global Assembly Cache for DevExpress.Web.ASPxGauges.vXX.Y.dll - -2147024891

Solution:

Use the Microsoft .NET Framework Repair Tool to restart and re-register Windows services, modify access control lists, and clear unnecessary/missing/incorrect files and directories in the GAC folder.