Troubleshooting

• Feb 02, 2024
• 3 minutes to read

This section describes common issues and steps you can follow to diagnose and resolve these issues. If the solutions listed here do not help, create a ticket in our Support Center.

To diagnose and collect detailed information about an issue, see the instructions listed in the following topic:

• Get Started (How to collect detailed information about the issue)
• KB Article: How to enable script debugging
• KB Article: How to determine the cause of an internal server error
• How to inspect CSS rules

Common Issues

• Clear Temporary ASP.NET Files
• Why the "Your session has expired" Error Might Occur

Client-Side Issues

• The 'X is undefined' error occurs or controls are rendered with incorrect styles
• Cannot access DevExpress ASP.NET controls on the client
• The 'ReferenceError: 'X' is not defined' error message appears when the Control.Enabled property is set to false
• The 'Microsoft JScript runtime error: 'X' is undefined' error message appears when the Control.Visible property is set to false

Server-Side Issues

• Cannot add duplicate collection entry of type 'add' with unique key attribute 'name' set to 'ASPxHttpHandlerModule'
• Icons, images, and scripts are missing
• The target 'X' for the callback could not be found or did not implement ICallbackEventHandler
• The controller for ASPxUploadProgressHandlerPage.ashx was not found or does not implement IController
• Internal Error. Unable to find the X resource in the Y
• Response.Redirect cannot be called in a Page callback
• Why it is impossible to download files on callbacks
• A primary key field specified using the KeyFieldName property is not found
• The 'Key expression is undefined' error occurs when you use LinqServerModeDataSource / EntityServerModeDataSource
• Data binding methods such as Eval(), XPath(), and Bind() can only be used for a databound control
• Could not find control 'X' in ControlParameter 'Y'
• 'The X has no access to path Y' or 'Access to the path X is denied' for File and Image Controls
• The 500.19 error - The requested page cannot be accessed because the related configuration data for the page is invalid
• Cannot unregister UpdatePanel with ID since it was not registered with the ScriptManager

Installation and Update Issues

• Cannot modify the Global Assembly Cache
• Type 'X' exists in both assemblies / Type 'X' is ambiguous in namespace 'Y'
• Could not load file or assembly 'Microsoft.Windows.Design.Extensibility ...'
• Could not load file or assembly 'X'

Performance Issues

• How To: Improve Page Rendering Speed
• How to: Improve Grid Performance

Grid-Related Issues

• How to: Improve Grid Performance
• The 'Specified method is not supported' and 'Updating is not supported by data source 'X' unless UpdateCommand is specified' errors occur
• Grid displays empty rows in database server mode
• The Click event of asp:ImageButton is not raised when the component is located inside a template
• The 'Row not found or changed' error occurs
• This action has been disabled for security reasons. The control cannot serialize complex primary key field values
• Sys.WebForms.PageRequestManagerParserErrorException: The message received from the server could not be parsed

Themes-Related Issues

• 'Cannot find the X theme' or 'Theme X cannot be found in the application or global theme directories' errors occur
• A theme or a skin file is not applied to an ASP.NET control descendant