If you want to upgrade and/or install K2 and integrate it with SharePoint 2010 ensure before you do that that sites are not locked. As part of the feature activation will need to deploy things to the sites and it cannot do this if they are locked .

This article has a pretty good way to quickly find which sites are locked:
http://www.sharepointdiary.com/2012/12/check-lock-status-for-all-site.html