Garbage in/Garbage out is always a possiblity, however 2sql statistics will help to identify problem objects.
If nothing else, 2sql provides a detail report on the status of the Access Database identifying problem areas and the ability to accurately estimate scope of project.
2sql works in 2 modes, report and update.
Run your database through 2sql for a report which summarise "errors" by type (Ansi89/Jet syntax, DAO to ADO, upsize queries to view, Referential Integrity are some of the 17 categories on the report I am looking at), click on a category then Detail to view the errors in that category in detail. The detail shows the line number, the line and whether 2sql can repair it.
On the report I have in front of me, 2sql identified 1690 errors advising that it was able to repair 1671 of them.
The remaining 19 need to be repaired manually.
This report allows preprocessing of problem areas before the migration.
This may require running reports a number of times after attending to premigration problems that need attention,
When Access application is clean, run 2sql in update mode to complete the process.