You have a computer that is running Microsoft SharePoint Designer 2010 or 2013.
You open and then make some changes to an external content type (ECT).
You save the ECT.
In this scenario, all resource data for a slice is deleted.
After you save an ECT that you have updated or changed, SharePoint Designer deletes the old version of the ECT and then creates a new version. As part of this delete operation, SharePoint Designer deletes any resource data that is associated with the ECT in the nondefault settings, such as the Client setting.
Note Resource data includes the LocalizedDisplayNames, AccessControlEntries and Properties elements.