Compatibility with Visual Studio Express Editions

By design of Microsoft, the Express Editions of Visual Studio do not support or allow tool extensions, including Visual Assist. This policy from Microsoft applies to tool extensions from all vendors, and to all versions of Visual Studio for which Express Editions are available.

Visual Studio Community, a newer IDE from Microsoft, does support extensions, including Visual Assist. If you use an Express Edition of the IDE, consider migrating to the Community edition if you want to run Visual Assist.