Note: This article was originally published in 2012. Some steps, commands, or software versions may have changed. Check the current Windows documentation for the latest information.

In this step-by-step guide, you’ll learn uninstall an assembly from the gac (using gactuil).

As a developer in general you’ll find yourself surrounded by (http://en.wikipedia.org/wiki/Revision_control “Revision control”) issues from time to time. Say for example, you are working with a particular (http://en.wikipedia.org/wiki/Library “Library”) during development and a new version comes out. Sometimes the problems you face using the correct version of the library can be resolved by removing the previous versions from the Global Assembly Cache (GAC). Many other reasons exist for wanting to do this. Perhaps you are coding this as part of an installer for your application. Any way, it is always good knowledge to have around. In order to remove or uninstall a library / DLL / Assembly from the GAC simply run the following at the command prompt:

gacutil /u <fully qualified assembly name >

Don’t forget you are going to need to run it using elevated credentials ((http://en.wikipedia.org/wiki/User_Account_Control “User Account Control”)) If you need more help or to see more options simply type:

gacutil /?

That command will launch the onscreen help for gacutil

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Summary

You’ve successfully learned uninstall an assembly from the gac (using gactuil). If you run into any issues, double-check the prerequisites and ensure your Windows environment is properly configured.