Mahedee Hasan

Mahedee Hasan

I am a Microsoft MVP (11th times), programmer, software developer, software architect, consultant, author, researcher, technical blogger, technical speaker, trainer and learner. I have more than 17 years experience in the field of software design and development.

Resolving ‘This Application Was Precompiled with Personalization Turned Off’ Error in ASP.NET

4 minute read

The Problem

When deploying ASP.NET applications to production servers, particularly on Windows Server environments, you might encounter a confusing error that prevents your application from running properly. This error typically appears immediately after deployment when attempting to browse any page in your application.

Error Details

The complete error message appears as follows:

This application was precompiled with personalization turned off, but it appears 
to have been turned on after the precompilation, which is not supported.

Description: An unhandled exception occurred during the execution of the current 
web request. Please review the stack trace for more information about the error 
and where it originated in the code.

Exception Details: System.Web.HttpException: This application was precompiled 
with personalization turned off, but it appears to have been turned on after 
the precompilation, which is not supported.

When This Error Occurs

This error commonly occurs in the following scenarios:

  • After deploying a precompiled ASP.NET application to a production server
  • When using Web Deployment Projects or publishing tools
  • During application pool recycles where configuration changes are detected
  • When deploying to shared hosting environments with different default configurations
  • After server migrations or framework updates

Root Cause Analysis

To understand this error, we need to examine two key ASP.NET concepts:

1. Precompilation

ASP.NET precompilation is a deployment optimization technique where:

  • Source code is compiled before deployment
  • Only compiled assemblies are deployed to the server
  • Runtime compilation is eliminated or minimized
  • Application startup performance is improved

2. Personalization

ASP.NET personalization is a feature that:

  • Allows storing user-specific settings and preferences
  • Uses the Profile system to manage user data
  • Requires runtime code generation capabilities
  • Conflicts with certain precompilation scenarios

The Conflict

The error occurs when:

  1. Your application was precompiled with personalization disabled
  2. The target server environment has personalization enabled by default
  3. ASP.NET detects this configuration mismatch and throws the exception

Solutions

The most straightforward solution is to explicitly disable the profile system in your web.config:

<configuration>
  <system.web>
    <!-- Disable ASP.NET Profile/Personalization -->
    <profile enabled="false" />
  </system.web>
</configuration>

Solution 2: Complete Profile Configuration Disable

For more comprehensive control, you can disable the entire profile system:

<configuration>
  <system.web>
    <profile enabled="false" automaticSaveEnabled="false">
      <!-- Remove any existing profile providers -->
      <providers>
        <clear />
      </providers>
    </profile>
  </system.web>
</configuration>

Solution 3: Machine-Level Configuration

If you have server access, you can modify the machine.config or web.config at the server level:

<!-- In machine.config or root web.config -->
<configuration>
  <system.web>
    <profile enabled="false" />
  </system.web>
</configuration>

Solution 4: Precompilation with Personalization

If you need personalization features, modify your precompilation process:

# Use aspnet_compiler with personalization support
aspnet_compiler -v /YourApp -p C:\Source\YourApp -u C:\Compiled\YourApp

The -u flag creates an updatable precompiled application that supports personalization.

Prevention Strategies

1. Environment-Specific Configuration

Use configuration transformations to handle different environments:

Web.config (Development)

<profile enabled="true" />

Web.Release.config (Production)

<profile enabled="false" xdt:Transform="Replace" />

2. Deployment Best Practices

<!-- Explicitly define profile settings in production deployments -->
<configuration>
  <system.web>
    <!-- Disable unnecessary features for precompiled apps -->
    <profile enabled="false" />
    <webParts>
      <personalization enabled="false" />
    </webParts>
    
    <!-- Other production optimizations -->
    <compilation debug="false" targetFramework="4.0" />
    <customErrors mode="On" defaultRedirect="~/Error.aspx" />
  </system.web>
</configuration>

3. Build Process Integration

Integrate the solution into your build process:

<!-- MSBuild target to ensure profile is disabled -->
<Target Name="DisableProfileForProduction" BeforeTargets="Build">
  <XmlPoke 
    XmlInputPath="web.config" 
    Query="/configuration/system.web/profile/@enabled" 
    Value="false" 
    Condition="'$(Configuration)' == 'Release'" />
</Target>

Troubleshooting Tips

Verify Current Configuration

Check your current profile configuration:

// In your code-behind or Global.asax
protected void Application_Start()
{
    bool profileEnabled = System.Web.Configuration.WebConfigurationManager
        .GetWebApplicationSection("system.web/profile") != null;
    
    System.Diagnostics.Debug.WriteLine($"Profile enabled: {profileEnabled}");
}

Common Configuration Locations

Check these files for conflicting profile settings:

  1. Application web.config - Your application’s configuration
  2. Site-level web.config - IIS site configuration
  3. Machine.config - Server-wide configuration
  4. Framework web.config - .NET Framework defaults

Deployment Checklist

  • Verify profile settings in web.config
  • Check precompilation flags used during build
  • Test deployment in staging environment
  • Confirm server-level configuration compatibility
  • Review application pool settings

Alternative Approaches

If You Need User Personalization

If your application requires user-specific settings:

  1. Custom Profile Implementation 
    // Use custom user preference storage
public class UserPreferences
{
    public void SaveUserSetting(string userId, string key, object value) { }
    public T GetUserSetting<T>(string userId, string key) { }
}
  2. Third-Party Solutions
    • Use external user preference services
    • Implement custom session-based storage
    • Utilize database-driven user settings
  3. Modern Alternatives
    • Client-side storage (localStorage, cookies)
    • RESTful user preference APIs
    • Cloud-based user profile services

Conclusion

The “This application was precompiled with personalization turned off” error is a common deployment issue that stems from configuration mismatches between development and production environments. The solution is typically straightforward: explicitly disable the profile system in your web.config file.

By adding <profile enabled="false" /> to your configuration, you resolve the immediate issue while maintaining your application’s precompiled performance benefits. For applications that truly need personalization features, consider modern alternatives or modify your precompilation strategy to support updatable deployments.

Remember to test your deployment process in a staging environment that mirrors your production setup to catch these configuration conflicts early in your development cycle.

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