When converting from desktop to online I get the message "for security intuit doesn't support this browser"

You need to convert data from QB Desktop UK version to QB Online UK version, correct? You have to use a conversion service provided by MMB

https://quickbooks.intuit.com/learn-support/en-uk/help-article/accounting-bookkeeping/move-quickbooks-desktop-quickbooks-online/L2XMo69EY_GB_en_GB?uid=lj8g166u

You will need to purchase another 3rd party service to convert data with other requirements (e.g multi currency, attachments). 

Hello John371, thanks for posting on the Community page, 

We have seen an increase in contacts from customers who are wanting to Migrate there data from QBDT to QBO due to Desktop being discontinued at the end of the month (30th June 2023).

You may not be aware that the old method of migration which was offered in the QBDT product, was discontinued in June 2022.

 It will display an error 'For security, Intuit does not support this browser or browser version.

You now need to use Movemybooks if you want to migrate from QBDT to QBO.

You will need to follow the link below: QuickBooks Desktop Migration to QBO via Move My Books:

https://quickbooks.intuit.com/learn-support/en-uk/help-article/accounting-bookkeeping/move-quickbooks-desktop-quickbooks-online/L2XMo69EY_GB_en_GB?uid=lg0yxi9p Also you will need to read the following links: Limitations Article: (Must read prior migration)

https://movemybooks.co.uk/move-to-quickbooks/limitations-of-service-quickbooks/ Post Migration Check: (Must follow after migration)

https://movemybooks.co.uk/move-to-quickbooks/post-conversion-tasks-quickbooks/