Sign in with Microsoft
Sign in or create an account.
Select a different account.
You have multiple accounts
Choose the account you want to sign in with.


If you click open the Debtor/Creditor Maintenance Options window or Company Setup Options window, you are not able to close the window if the Tax Registration field is left blank and the country code is GB.  Themessage below is given:

Please enter a valid tax registration number.

OB Number validation failed for Tax Registration field.


A validation runs on the Tax Registration field if the country code is set to 'GB' for company/debtor/creditor, and VAT Daybook is installed.  The tax registration field cannot be blank for the country code GB.  (VAT Daybook access is given under Microsoft Dynamics GP | Tools | Setup | System | Use VAT Daybook.)   

Most often users entered a tax registration number, but did not enter it in the correct format.  It cannot contain any letters or spaces. 



If the Tax Registration field should be filled in, please check the below:

Option 1 - If you have a valid Tax Registration number and are still getting this message, you may be entering it into Dynamics GP incorrectly. A validation is run on this field and you must enter the number without any letters or spaces.

You will have your own unique Tax Registration number for your company.

As an example, if your Tax Registration number is: GB 999 9999 73

Enter it in the Tax Registration field in Microsoft Dynamics GP like this: 999999973
(no letters or spaces)

Option 2 - Test with the 'sa' login to see if the system administrator gets the same error in the same window.  If not, then the user ID may be corrupt.  Copy the security for the problem user over to a new temp user ID and see if the user experiences the same issue.  If not, then delete their problem user id and re-set it up. 

If the Tax Registration field should be 'blank', the work-arounds are:

Option 1 - When you are stuck in the Debtor or Creditor Maintenance Options window or Company Setup Options window, drag the Options window out of the way and delete the Country code of 'GB' on the main Debtor or Credit Maintenance window or Company Setup window. (After you clear out the country code of  'GB' and you must TAB off the field to accept the change.) Now you can close the Options window. Re-enter the country code of 'GB' back on the Debtor/Creditor/Company window again and Save.  (CR 86997)

Option2 - If you are not using VAT Daybook, you can disable/remove access to it by going to Microsoft Dynamics GP | Tools | Setup | System | Use VAT Daybook and unmark the checkbox in the 'Use VAT Daybook' column for the Company.

Need more help?

Want more options?

Explore subscription benefits, browse training courses, learn how to secure your device, and more.

Communities help you ask and answer questions, give feedback, and hear from experts with rich knowledge.

Was this information helpful?

What affected your experience?
By pressing submit, your feedback will be used to improve Microsoft products and services. Your IT admin will be able to collect this data. Privacy Statement.

Thank you for your feedback!