Error 1088: Failed to execute request because the App-Domain could not be created

Problem

You attempt to connect to a new web application, and you experience this message in the browser:

The web application you are attempting to access on this web server is currently unavailable. Please hit the "Refresh" button in your web browser to retry your request.

You check the application event logs and find the following errors:

Event Type: Error
Event Source: ASP.NET 2.0.50727.0
Event Category: None
Event ID: 1088
Date:  10/1/2013
Time:  3:14:20 PM
User:  N/A
Computer: SPDEV23
Description:
Failed to execute request because the App-Domain could not be created. Error: 0x80070005 Access is denied. 
For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

Event Type: Error
Event Source: ASP.NET 2.0.50727.0
Event Category: None
Event ID: 1334
Date:  10/1/2013
Time:  3:14:20 PM
User:  N/A
Computer: SPDEV23
Description:
Failed to initialize the AppDomain:/LM/W3SVC/1153737112/Root
Exception: System.IO.FileLoadException
Message: Could not load file or assembly 'System.Web, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. Access is denied.
StackTrace:    at System.Reflection.Assembly._nLoad(AssemblyName fileName,...
.
.

Resolution

This issue can occur after installing service packs and not rebooting.

1. First, perform: iisreset.
2. Then, if that fails to resolve the error, perform:
• C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\aspnet_regiis -i.

References

• ASP.NET Forums: Failed to execute request because the App-Domain could not be created. Error: 0x80070005 Access is denied
• ASP.NET Forums: The web application you are attempting to access on this web server is currently unavailable. Please hit the "Refresh" button in your web browser to retry your request