We heavily advise using “Overwrite” to avoid duplication and to ensure as few duplicates as possible.
Where possible, we advise importing customers to Books first (so that you have Tax data already imported).
If that can’t work, then try to make sure that one of the databases is empty of Customers.
BE VERY CAREFUL of implementing “Overwrite” if you already have data in both applications, or you may end up duplicating/deleting certain information.
You can mitigate this risk by doing an Excel VLOOKUP table to see how much overlap there is.
It’s worth checking in with Zoho Books support to say “Hey, how will this look? Will I screw anything up?”
