Hello there, seb2.
There are times that your default browser is filled with data and temporary files from previously visited websites. With this said, I recommend using a private browser. Doing so helps isolate the issue. You can use the keyboard shortcuts below:
Once you've opened a private browser, try to create a new invoice again. If it works, to ensure this doesn't happen again, it's a good idea to clear the cache of the browser you're using or trying other supported browsers.
I'll appreciate if you can get back to me and share how it works. I want to ensure that this gets resolved. Have a great day!
Great to know you're able to create an invoice on another browser, seb2.
Have you tried clearing the browser cache in an All time option? If not, let's try deleting the browser data in that time frame. Just follow the steps in this article: https://support.google.com/chrome/answer/2392709?hl=en.
Then, let's make sure Chrome is updated to the latest security updates. You can check out this article on how to update Google Chrome: https://support.google.com/chrome/answer/95414?co=GENIE.Platform%3DDesktop&hl=en.
Once done, try creating a new invoice using your default browser.
I've got a link here that contains articles about managing customers and income: https://quickbooks.intuit.com/learn-support/manage-customers-and-income/misc/02/uk-manage-customers-....
Feel free to come back to this thread if you need anything else with managing your invoices. I'll be here to help.