Site Columns and Site Content Types are a great feature of SharePoint. They’re easy to create/modify and provide granular configuration capabilities. It’s commonly known that the Title Site Column can’t be removed from Site Content Types (or List Content Types, for that matter); it’s attached to the Item Base Content Type, after all.
But did you know that there are many Site Columns that can’t be removed from Site or List Content Types?
Below is a list of Site Columns confirmed to be persistent on Site & List Content Types in SharePoint 2010.
|Display Name||Internal Name|
|Contact E-Mail Address||PublishingContactEmail|
|Properties used in Conditions||RoutingConditionProperties|
|Property for Automatic Folder Creation||RoutingAutoFolderProp|
|Route To External Location||RoutingRuleExternal|
|Scheduling End Date||PublishingExpirationDate|
|Scheduling Start Date||PublishingStartDate|
|Submission Content Type||RoutingContentType|
|Summary Links 2||SummaryLinks2|
UPDATE (11 MAY 2011)
It appears that Site Content Types that using or having used one or more “persistent Site Columns” cannot be deleted. A custom Site Content Type (named “Service”) was used to test behavior of these persistent Site Columns. It could not be deleted through the SharePoint web UI due to an error stating: “The content type is in use.”
To confirm Site Content Type usage, each List and Site Content Type was inspected; no objects were found to use the “Service” Site Content Type. Using SharePoint Manager 2010, it was confirmed that the Site Content Type was not being used.
Unfortunately, the “Service” Site Content Type could not be deleted using SharePoint Manager 2010 due to an error stating: “Exception has been thrown by the target of an invocation.” Under the suspicion that the persistent Site Columns were causing unanticipated behavior, they were removed from the “Service” Site Content Type using Get-SPScripts’ PowerShell scripts through the SharePoint 2010 Management Shell. Unfortunately, the “Service” Site Content Type still could not be deleted using the SharePoint web UI, SharePoint Manager 2010, or PowerShell scripts.