Hello there, @SteveAJFF.
It's my pleasure to help you today so you'll be able to modify the existing budget successfully.
To single out the cause of this unexpected behavior, you can start by logging in your account using a private browser and start modifying the existing budget from there. To access your account using a private browser, you may use either of the following shortcut keys:
- Google Chrome, press CTRL + Shift + N
- Mozilla Firefox: press CTRL + Shift + P
- Internet Explorer: press CTRL + Shift + P
- Safari: press Command + Shift + N
If you're able to modify the budget using a private browser, you have clear the cache of the regular browser you're using. In addition, you can also try using another supported browser to help us narrow down the cause of this issue.
In addition, you can read this article to learn more about budgets: How to create, edit, and manage budgets.
However, if the issue persists, I recommend getting in touch with our Support Team to check and verify this further securely. For the support's contact information, you may check it here: Contact the QuickBooks Online Customer Support team.
Please feel free to add a post/comment below if you have any other questions about budgets, I'll be always here to help you however I can. Have a good day ahead!
