I downloaded csv files to back date my accounting. Lots of dates have come through as 0.00. Without having to go through every single transaction, how do I rectify this? Or how do I rectify every transaction if there is no other way.

Hello there, @emtgodfrey. 

Welcome and thank you for posting here in the Community. 

I'm here to get the help you need to ensure that you'd able to import your bank transactions. 

Make sure that the amount is the same as what is on the CSV file. Then, exclude the incorrect transactions. If everything is correct, you can reimport the file again. 

Then follow the right formatting in the Common errors for importing bank transactions using CSV article. Once done, try uploading bank transactions from .CSV to QBO again. 

I've got this awesome article that you can use as your guide in adding older transactions to QuickBooks Self-Employed. I'm also attaching our page about importing bank transactions using Excel CVS files for your reference.

Stay in touch if you have other questions about QuickBooks. I'd be glad to help. Thanks for joining the Community and have a good one. Cheers!