How to properly condense your QuickBooks data file
An often asked question is "what happens if I want to create a new company file, will it create a problem with my data sync?"
The short answer to that question is "yes, it will". However you can likely achieve what you are wanting to do by following this tutorial.
In most cases, there is really no need to actually create a new company file. The reason you don't want to just create a new file is that all your list IDs are going to be recreated and will no longer match the lists in your portal. Customers will no longer match to invoices, payments, etc. So this is really not an option for most people.
The way to properly create a new company file or condense your data is to use the Condense Data Utility. The following screencast will show you how to do this and what things you need to watch out for to ensure your data integrity is maintained.
In ALL cases, make a backup before performing any of these tasks.