Thanks for joining and sharing the details of your concern in this thread, @Bob_R1.

Let me share some troubleshooting steps you can use to fix the error message and file your VATfor this week. 

We can create a VAT adjustment so you don't have to worry about making corrections when it’s time to file. This will zero out your outstanding return and adjust the VAT that you owe.

Here's how:

Step 1: Set up an account for VAT adjustment

It’s important to use the correct account type when adjusting VAT. Set up an expense account if you need to increase your VAT due, or an income account if you need to decrease.

1. Click the Gear icon at the top and select Chart of accounts (Take me there).
2. Select New at the top right.
3. From the Account Type drop-down list, choose Income or Expenses.
   • If you need to decrease your VAT due, set up an income account.
   • If you need to increase your VAT due, set up an expense account.
4. Select the account’s Detail Type.
   • Use Sales of Product Income for an income account.
   • Use Taxes Paid for an expense account.
5. Name your adjustment account.
6. Click Save and Close.

Step 2: Add an adjustment

1. Go to the Taxes menu and select VAT (Take me there).
2. Find the tax period you need to adjust, then click Prepare return.
3. Click Adjust against the entry to be adjusted.
4. Select the Adjustment date and the Tax rate.
5. Choose the Adjustment account for adjusting VAT.
   • If you need to increase the tax due, select an expense account 
   • Choose an income account if you need to decrease the tax due.
6. Enter the Adjustment amount and notes in Memo, then select Save.

Then, you can update your VAT settings to update your Vat registration number. Afterward, you can now file your VAT. 

In case you need further assistance in handling your account. I'd recommend reaching out to QuickBooks UK Customer Support Group. 

For additional reference in handling your VAR in QuickBooks, you can check out these links:
 

• List of the common VAT codes in QuickBooks Online.
• Learn how to submit a VAT return to HMRC.

Let me know if you need further assistance with this. I'm always around to provide answers and clarifications to your questions. Have a great day ahead and take care.