TFS Integration Tool number of change groups doubling

Question

I have started using TFS Integration Tools to migrate work items from one TFS2010 project to another team project within the same collection. After some small trial runs and modifications to the field and value mappings I started a migration on our entire product backlog. Approximately 170000 change groups were discovered and analyse started. However, during the analysis the connection to the TFS server was lost so the migration had to be restarted. After the restart approx 340000 change groups were identified (roughly double) without any significant changes being made to work items in the backlog.

Has anyone experienced a similar problem or are aware of settings or changes that can be made in the tool to limit this increase in change groups? The amount of time taken to analyse so many groups is causing the migration to take much longer that was initially expected.

Answer 1

After several runs, I found out that the count appears to be a running total so logically enough when I experienced a break in connection all change groups had to be re-analysed causing the "doubling" in change groups.