Can't add System.Data.Linq or System.Web to project

Question

I can't add System.Data.Linq or System.Web to project, each time I do I get a warning symbol yellow !, on the reference

Any ideas why?

I had it working all okay this morning

Answer 1

Did you change the .Net version of the project.

System.Data.Linq does not work for .Net 2.0.

Answer 2

you just need to go to solution explorer and right click on the references > add references > search for system.data.linq. Hope it work

Answer 3

Sounds like the path to the DLL may no longer be valid. Try removing the reference and adding it in again...

Answer 4

I've had to create a new project and copy the classes and now it is working.

Answer 5

Right-click your project, select "Properties", then hit the "Application" tab. De-select "Client-only Framework subset". Grit your teeth at the annoying lack of detail you were getting before. (It just says "can't add reference".)