Occasional "Access denied" to 'C:\WINDOWS\TEMP\' files

Question

In my ASP.NET MVC application I sometimes get these errors when I try to open or generate LocalReport from Microsoft Reporting Services assembly:

Microsoft.Reporting.WebForms.LocalProcessingException: An error occurred during local report processing. ---> Microsoft.Reporting.DefinitionInvalidException: The definition of the report 'C:\Inetpub\wwwroot\orders\Reports\Reports\Pending Renewals.rdlc' is invalid. ---> Microsoft.ReportingServices.ReportProcessing.ReportProcessingException: An unexpected error occurred in Report Processing. ---> System.UnauthorizedAccessException: Access to the path 'C:\WINDOWS\TEMP\expression_host_b5ec9f67a3ab42cfb53a75588aed6f75.dll' is denied.

or

System.Web.HttpUnhandledException: Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> Microsoft.Reporting.WebForms.LocalProcessingException: An error occurred during local report processing. ---> Microsoft.Reporting.DefinitionInvalidException: The definition of the report 'Main Report' is invalid. ---> Microsoft.ReportingServices.ReportProcessing.ReportProcessingException: An unexpected error occurred in Report Processing. ---> System.UnauthorizedAccessException: Access to the path 'C:\WINDOWS\TEMP\expression_host_a1670a6e6b96411790645cb12e50897d.dll' is denied.

What can be the reason? Most of the time it works so it's not security issue. How do I fix it?

Here's what I've found but I'd not like to use "use fields instead of report parameters" solution.

Answer 1

I have the same issue: while exporting a report for printing, sometimes I get this exception and sometimes I don't ... At least now I know I'm not alone in experiencing this issue.