Could not load file or assembly or one of its dependencies

[Aangiix3]

I recently added hsProgressbar.dll to my Program, it worked fine, but then I decided to remove it from my Computer and also remove it from the references...however..the Warning is still there? How can I completely remove it, so that I don't get the error anymore?

Thanks in advance.

[Aangiix3]

SOLUTION:
I just went to Toolbox Items, clicked on Reset, closed and reopened the Project, and the warning disappeared.