Error 25015: "Failed to install assembly"
Error 25015: Failed to install assembly occurs when installing Microsoft .NET which is used by TurboTax.
This error is a Microsoft .NET issue. The .NET Framework is an integral part of Windows operating systems today, and we rely on the stability of integral system components. To the extent there are problems with .NET or any other system component, we do our best to troubleshoot the issue, even though it may be outside of our control.
Solutions
Identify your error below, and then follow the steps to resolve it:
Follow the steps below to rename the .NET 2.0 folder.
- Right-click the Start button and then choose Explore.
- Browse to C:\WINDOWS\Microsoft.NET\Framework.
- Right-click the v2.0.50727 folder, and the select Rename.

- Type v2.0.50727-OLD, and then press Enter.

- Install the TurboTax CD or download. (TurboTax installs .NET.)
Follow these steps to download, install, and run the .NET cleanup tool:
- Close all browser windows and programs.
- Download the .NET cleanup tool and save it on your desktop.
- Run the tool by double-clicking the download on your desktop.

- Restart your computer.
- Install TurboTax.
Note: The updated version of the .NET cleanup tool above comes courtesy of Aaron Stebner's WebLog. Stebner is a Microsoft employee and .NET expert.
Temporarily turn off your virus-detection software, and then install TurboTax.