When you try to install the .NET Framework, you receive an error 1935 (assembly install failure) error message if Mscoree.dll is in use before you start Setup. CAUSE
This behavior occurs because Mscoree.dll is held in use for 10 minutes after you install (or remove) the assemblies. When you start another install, the installer tries to load its own version of Mscoree.dll to install the assemblies for the new program. Because another version of Mscoree.dll is already loaded, the failure occurs.
This is because of Windows Installer behavior on Windows NT platforms. RESOLUTION
You can use either of the following methods to resolve this problem:
• Restart your computer.