A user can rename or move a point or accumulator in ClearSCADA after HCAL creates the Wonderware Historian tag for it. In this situation, the tag name will not match the ClearSCADA database item's current name (unless you have used the RenameTag method to realign the two names).
To find a tag name in ClearSCADA, view the Wonderware Historian Export status attribute in the Status display for the ClearSCADA point or accumulator.
Further Information
Wonderware Historian Driver-Specific Status Display Attributes.