In order to edit add-ins, their version has to correspond to the version of GN4 client applications installed on your workstation, that in turn, have to correspond to the version of GN4 server. If any of above is out-of-sync, you won't be able to test your changes by compiling add-ins.

The best test of compatibility of your add-ins and your GN4 applications after download of either, is to try to compile add-ins immediately after download, and in any case before you did any change.

To test of compatibility of your add-ins and your GN4 applications:

1.Make sure your GN4 client applications are not running, otherwise, exit all the GN4 client applications.

2.Load your GN4 add-ins solution (GN4AddInsExpress.sln) in Visual Studio Express as explained in Open GN4 add-ins in Visual Studio Express.

3.On the Build menu, click Build solution. Note: it's not important which add-in is selected or opened - the compile always regards the entire solution.

If everything is ok, the Visual Studio Express status bar (bottom left corner) will read: Build succeeded. This means the GN4 applications and add-ins are in sync.

If there are errors displayed, look at Compilation errors to understand the problem.