Stellarcreatemailbox.dll error occurs when a user is trying to create Exchange mailbox on the server. This error can be resolved by adding the legacy .NET Framework 2.0 in the system

 Steps to resolve Exchange Stellarcreatemailbox.dll error:

  1. Go to Control Panel >> Programs and Features. In the left pane, click Turn Windows Features On or off.

     

  2. Select the Checkbox for .NET Framework 3.5 (Includes .NET 2.0 and 3.0), and click OK.

     

  3. Uninstall and reinstall the software Stellar Repair for Exchange to reflect the changes.

Exchange Stellarcreatemailbox.dll error is resolved.