“Server Error in '/' Application” After Installing/Upgrading Backup Enterprise Manager

Challenge

Cause

Veeam Backup Enterprise Manager has not been upgraded correctly or ASP is running a 32 bit version when it should be running a 64bit version.

Solution

To resolve, reinstall Veeam Backup Enterprise Manager or force ASP to run in 64bit mode.

NOTE: If this error occurs after an upgrade of the software, please reinstall the Backup Enterprise Manager.
 
If this error appears from a fresh install of the Backup Enterprise Manager, please follow the troubleshooting below to try and resolve the issue.
 
After installing Veeam Enterprise Manager, you try to access it via the URL and you get an error having to do with Veeam.Common application error. The issue here is that IIS is running a 32bit version of ASP and it needs to be forced to 64bit, which can be done using the following MS Knowledgebase. After running the two commands below in step #3 and #4 you can simply open Backup Enterprise Manager and you will get the login screen successfully.
 
http://support.microsoft.com/kb/894435
 
To run the 64-bit version of ASP.NET 2.0, follow these steps:
 
1. Click Start, click Run, type cmd, and then click OK.
 
2. Type the following command to disable the 32-bit mode:
 

1. In IIS manager,  select “Application Pools".
2. Right click the “VeeamBackup”, choose “Advanced settings”.
3. You will see the “Enable 32-bit Application” option under “General”. Change it from True to False.