Event ID 1325, 1026, and 1000 after you convert OAB for Exchange Server 2010

Original KB number:   2961921


This issue occurs if you run the ConvertOABVdir.ps1 script on the Client Access Server that is running Windows Server 2012. Additionally, you can't download the OAB. Check out the resolutions to resolve this issue.


This issue occurs because the ConvertOABVdir.ps1 script configures the MSExchangeOabAppPool application pool to run .NET CLR Version 4.0 when the script is executed on a server that is running Windows Server 2012.


To resolve this issue, change the MSExchangeOabAppPool application pool to use .NET CLR Version 2.0. To do this, use one of the following methods.

Method 1: Use IIS Manager

  1. Open Internet Information Services (IIS) Manager on the Client Access Server, expand the server object, and then select Application Pools.
  2. Right-click MSExchangeOabAppPool, and then select Basic Settings.
  3. Select .NET CLR Version v2.0.50727 from the .NET CLR version drop-down list and then click OK.
  4. Right-click MSExchangeOabAppPool and select Stop.
  5. Right-click MSExchangeOabAppPool and select Start.

Method 2: Run script

Use a text editor to copy the original script without the trailing signature block (beginning at line 161) into a new script file, such as a My-ConvertOABVdir.ps1 file.

Add the $apppool.ManagedRuntimeVersion = "v2.0" line after line #31 to create the .NET CLR Version 2.0 application pool in your .ps1 file. Then, execute your .ps1 file.

The following is a part of sample of this script:

#29 # Create new app pool, then bind to it
#30 $a=$Iis.applicationPools.Add("MSExchangeOabAppPool")
#31 $apppool = $Iis.ApplicationPools["MSExchangeOabAppPool"]

#33 # add this line: make sure we create a .Net v2.0 app pool, regardless off underlying OS.
#34 $apppool.ManagedRuntimeVersion = "v2.0"

#36 # Now make sure it runs as LocalSystem, and prevent unnecessary app pool restarts
#37 $apppool.ProcessModel.IdentityType = [Microsoft.Web.Administration.ProcessModelIdentityType]"LocalSystem"
#38 $apppool.ProcessModel.idleTimeout = "0.00:00:00"
#39 $apppool.Recycling.PeriodicRestart.time = "0.00:00:00"


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in Applies to.