MatchUp Software:Excel/Access Troubleshooting Guide
Troubleshooting Tips When Processing an Access or Excel Table
Access and Excel are difficult formats to process because they are in a proprietary Microsoft format. Because of this, we are forced to use Microsoft's prescribed methods to access data. MatchUp uses one of two technologies for doing this: ADO and DAO. This document is intended to provide steps in working around the default behavior and providing MatchUp with formats it can handle.
Add an Autonumber field to your table.
One of the biggest problems with DAO/ADO is that these technologies were written with the assumption that people always access their data in a linear fashion, from start to end. While MatchUp does do this while building keys, it must access the data in a random sequence when it is performing the merge/purge operation. Another way to explain this is to say that DAO/ADO do not use record numbers. So when MatchUp tells DAO/ADO to move to record 58, DAO/ADO uses an awkward (and apparently buggy) algorithm to accomplish this. Adding an autonumber field essentially provides a record number field for your table, saving DAO/ADO from sweating out the computations.