Thanks for reaching out, @lizarooo.
Let me get the help you need in categorizing your mileage trips in QuickBooks Self-Employed (QBSE).
To start, try opening your account in a private (incognito) window. Using a safe browser and accessing the program from there can usually fix the issue.
Check out these keyboard shortcuts:
Once done, try to categorize your trips again.
If it works, go back to your default browser and clear cache. See Clear cache and cookies to fix issues when using QuickBooks Online for more information.
Otherwise, switch to a different supported browser. The one you are currently on may be having a temporary issue with QuickBooks, and using a new browser for the moment will allow you to get back to work.
To know more about how the Mileage feature works in QBSE, see the below articles:
Please let me know how it goes, as I want to ensure that you're able to categorize your trips. Wishing you well.
Hi there, @lizarooo.
I appreciate the things that you've done to fix the issue.
It would be best to contact our Customer Care Team since you've already modified each transaction manually. This is done to check why you're not able to save the options when using the batch feature on the Miles page.
I've added these articles for your future reference about mileage tracking troubleshooting method:
I'll be here if you have other questions. Let me know in the comment section below. Take care.