Thank you for your reply.

Your suggestion would work under normal circumstances but, given that it is Year End and they can't wait, I looked for another solution.

A Data Repair would solve the problem. But a faster solution was to edit the AR Global file and reset the posting sequence number using an external editor.

For the record, I discovered that the problem existed in the client's ACCPAC Plus data from BEFORE it was converted to Adagio.

The problem is now solved.