When trying to file VAT return to HMRC, I get the message; you must also click save again to make this change that is prior to the closing date. what does this mean

Good day, prolink_building.

You will get this error message when a closing date is entered under the Close the books section in the settings. You'll want to turn it off by following these steps:

1. Go to the Gear > Account and Settings.
2. On the left panel, select Advanced.
3. Click Accounting to expand the options, and un-check the Close the books option.
4. Click Save and then Done.

Once done, file the VAT return to the HMRC again. 

For more information about closing the books and file the VAT return, here are some articles: 

• Close your books to lock past transactions
• Submit a VAT return in QuickBooks Online

I'm just a post away if you need more help with QuickBooks Online. Stay safe.