Dll's in the GAC are not embedded into the client. My guess is that it is a versioning issue. When you re-install version 2 of a dll in the GAC it keeps version 1 so that clients that refer to version 1 will not break. This is side-by-side versioning.

Use GacUtil or Windows explorer to view your Assembly directory to see which versions of the dll are in the GAC. Then look at the properties of the reference to the assembly in the project to see which version it is referencing. Also, when moving the reference from a local version of the dll to the gac version I have had to delete and add back the reference before it handled it correctly.

Working with the GAC is a little foreign so it takes some getting used to. It confuses me all the time.

>Are .dll files compiled into the web service program?
>
>If I make a change to an object file (.dll) and install it in the GAC, the client program does not know about the change. I've found that if I recompile the client, *then* it will recognize the new behaviours in the .dll...
>
>Am I mistaken in believing the following:
>
>- I can build a business object into a .dll file and install it in the GAC
>- I can build client programs to access this business object remotely on a LAN, WAN, internet, whatever.
>- I can change the logic in the business object and re-install a new .dll in the GAC
>- All the client programs will behave according to the new business object's logic
>
>Is the .dll compiled into the client? It seems to be, regardless of the setting of "Copy local"...
>
>Now, I'm asking this question for a third party, so I'm fuzzy about the details, but I too am confused about his findings...
>
>TIA