I had the similar problem quite recently. This solved it: Forum: Visual FoxPro Category: Troubleshooting Title: Re: Error 1547 Thread #521182 Message #521192

>If you are using the "Default value" to generate your unique ID in your DBC, I can tell you that when I did APPEND BLANK it gave me the "uniqueness Index" error. I had to use INSERT INTO ... and it works like a charm.
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>Why? - who knows...
>Does it append a blank record and then tries to replace the primary key field with the next ID code and thinks that someone is using the record? - again, who know...
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>>Nope, I'm using a straight ole "append blank" here because the code in this section is very generic. I could write a case statement for all of the screens and use that to create an "insert" statement with fields and values but it seemed easier (?) to append blank and then replace.