Symptoms
When tried to Activate All K2 Features and K2 Configuration Settings for a site collection, got "An entry with the same key already exists." error.
Diagnoses
Duplicate 'SharePoint Site URL' name in Environment Fields.
Resolution
Using Workspace, check the 'SharePoint Site URL' environment fields for each environment to see if there are any with the same name and if so, try to delete or rename one of them:
-Navigate to Management -> Management Console
-Expand the K2 Server node
-Expand the Environment Library node
-Expand the Templates node
-Expand the Default Template node
-Expand the Environments node
-For each environment listed, expand the node and select Environment Fields
-Make sure there are no fields with a 'Field Type' of "SharePoint Site URL" that have the same name
