Hi Eloise

Duplicate check numbers are permitted, even to the same vendor, but shouldn't occur in the same check run, assuming you printed the checks using Print/Post Checks and Advices and not the Manual Check function. So that is odd. And it is definitely odd that the check register combined the two payments onto one vendor.

By chance, did you say No when asked if the checks printed OK, and then reprint one or more, or did you say Yes?

Definitely make a backup and perform Data Integrity Check on your AP data. There may be some data corruption. Click on Rebuild if any errors are found.

Also, what version and version and release date of AP are you using - the latest is AP 8.1A (080821)? If it is not this version, there is no reason not to upgrade.

Steve