Exclamation mark problem on dll?

I've added a DLL to my project, written with visual studio 2005.

After I did so, an exclamation mark appears nearby the added DLL.

I want开发者_高级运维 to not having this exclamation mark because I'm assume its reflect about a problem.

A friend of me added this DLL to his project on this computer and everything worked well, so I assume I didn't added it well nor there is a problem in my visual studio/computer.

Any ideas how to handle it?

I had the same problem when Target framework of destination project and the version of references was different. After I've changed it Project properties, it worked.

This usually means that VS can't find the assembly. Make sure it's in a location that is accessible to you, and compare this with your friend's. E.g., is it on a co-worker's machine that may be turned off at certain times? Is it on a network drive?

I'd suggest making a local copy of the file and seeing if the problem is solved.

Question is a possible duplicate of this one.