You may be able to make your life easier if you use the Audit Logs to show the advancement approved between now and a day before you approved everything. That way, you should have a list of everything that got approved to use as a “roadmap” for the “manual undo” process. :^)
I believe you need to be a unit admin, Key 3 Member, or Key 3 Delegate to access the report. It can be found here:
My Dashboard → Administration → My Units → Unit Reports → Audit Log Report
then select only the Advancement Log tickbox and choose your timeframe.
Can you tell I’ve done this once or twice before myself? :^)
