How can I block back date entries?

Hi, radphotography3-. 

Welcome to the Community. I can assist you with backdating entries in QuickBooks. The back date usually happen when you created the journal entry and used the Undeposited Funds as an account.

If you don't want the journal entry to appear on your list, make sure to use any account aside from Undeposited funds.  

Let me guide you how:

1. On your left navigation pane, click on +New.
2. Under Other column, select Journal entry.
3. Under the Account column choose any account aside from Undeposited funds.
4. Once done, press Save. 

However, if you referring to something else like delete backdate entries, you can refer to the link provided. Though, additional information will help rectify the issue.   

I'm always available here if you have additional questions concerning your QuickBooks data. You can reach out to me by posting your response.