Very often update query is not working when Excel is connected using connection string (oledb)

I suspect the issue here is that when Excel is started by an automation it doesn’t refresh queries. The easiest way to fix this is to upgrade to the newest version of the Excel activities (2.10.4) and leverage the “Refresh Excel Data Connections” activity that was added to the StudioX->Business->Excel activities. If you are in Studio, see this for how to use the activity in Studio.