Symptoms

When clicking the link for the K2 Configuration Wizard from SharePoint Central Admin (for K2 for SharePoint 2013 in 2010 Compatibility Mode), specifically when accessing "Activate All K2 Features and K2 Configuration Settings" (/ActivateComponents.aspx) then the following error occurs:

Invalid Archive Type
 

Diagnoses

It seems the version of K2 installed on the SharePoint server and the version installed on the K2 server are different. We found that version 4.6.11 was installed on the SharePoint server, but the K2 server was still on 4.6.9

 

Resolution

After upgrading the K2 server to the latest version 4.6.11 as well using the Update Manager, the issue was resolved.