We have seen several cases of an issue whereby folders are getting locked in KTA.
Upon unlocking them, they are then going to the Validation (IPA) activity to try to process the invoice.
However they are unable to validate the invoices as they see a "PRIMARY KEY constraint"
There is an issue with the ForceUnlockItem() method in KTA v7.9 in that it doesn't remove the entries from the CachedDocument table. This issue is also resolved in KTA v7.10.
Please upgrade KTA to version 7.10
For a short term solution, you could go to the Job Details -> Unlock UI to unlock a locked folder/document.
Level of Complexity
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Article # 3045327