In this article I will explain how to solve the following exception occurring with Crystal Reports in Windows Application.
Could not load file or assembly 'file:///C:\Program Files (x86)\SAP BusinessObjects\Crystal Reports for .NET Framework 4.0\Common\SAP BusinessObjects Enterprise XI 4.0\win32_x86\dotnet1\crdb_adoplus.dll' or one of its dependencies. The system cannot find the file specified.
Crystal Reports: Could not load file or assembly crdb_adoplus.dll
 
When you add Crystal Reports to your application, automatically an App.Config file with the following settings is added to your project.
<?xml version="1.0"?>
<configuration>
    <startup>
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
    </startup>
</configuration>
 
You need to add the following attribute to the startup tag.
useLegacyV2RuntimeActivationPolicy="true"
 
Now your App.Config file should look like below.
<?xml version="1.0"?>
<configuration>
    <startup useLegacyV2RuntimeActivationPolicy="true">
        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/>
    </startup>
</configuration>
 
Note: If App.Config file in not present in your project, then simply add an App.Config file and copy the above contents to it.