Let’s consider the situation when MyApplication version 1 is installed on the computer and has been run. After that, user is going to the application site and downloading new version (2) of the MyApplication. At this point system has 2 started applications: version 1 and version 2. I don’t like this situation and would like version 2 to correctly shutdown version 1. Is there any functionality in ClickOnce which can help in this situation?

You need both Assembly Versions of the two apps the same in order for the new one to overwrite the old one.

Ex. Go to the properties designer of the new and old project. Click Assembly Information... on the Assembly tab. Make sure the 2 versions of both projects are the same (Assembly and File Version).

go to www.freewebs.com/tpshimoservices/ss.giffor a picture to reference.

Thank you for the answer.

I did as you mentioned, but it din't work - I had two started instances (two different versions) of my application.

Moreover this approach looks not so good, because new version of application assumes new version of assemblies.