Solution to "TF212018: Work item tracking schema validation error: TF26085: Unknown constant with id 3675334." when importing a WIT into TFS

If you get this exception: “TF212018: Work item tracking schema validation error: TF26085: Unknown constant
with id 3675334.” when calling witadmin importwitd, then your cache is likely invalid.

Just clear your cache and rerun the witadmin command.

Jon