Symptoms

K2 installation questions:

Is it necessary to install K2 smartforms and K2 smartforms Control Pack on all of our servers (K2, SharePoint application, SharePoint WFE)?

In case these components already installed on all servers (K2, SharePoint APP and SharePoint WFE) can they be removed from SharePoint servers and what is the procedure?
 

Diagnoses

You only need to install K2 smartforms and K2 smarfroms Control Pack on the K2 Server in case you are using SharePoint 2013.

If you have SharePoint 2010 you need to install K2 components on all SharePoint servers. Only K2 for SharePoint component have to be installed on your SharePoint 2010 servers, so make sure you do a custom installation and that you only select the components you need. Refer to the following section of K2 Product documentation for details: Install K2 for SharePoint component on the SharePoint Server.

However, if you use SharePoint 2013, then you only need to deploy the K2 app on the SharePoint 2013 server using AppDeployment.exe.
 

Resolution

Answer depends on SharePoint version you are using (2010/2013) and your installation topology. See Diagnosis section for details.