How can I manually enter vendor ACH information without it disappearing?

Try opening your QBO account on any private/incognito browser.

We appreciate you bringing this up here in the Community, seamusiclover.

There's an ongoing investigation regarding the vendor ACH information issue, which disappears after saving. Our product engineers dedicate their time and effort to the necessary fixes to keep everything working as designed.

Currently, we don't have the exact time frame for resolution yet. Hence, I recommend contacting our customer support team so they can add you to the list of affected users. This way, you'll receive timely updates via email regarding the progress of this case.

Here's how:

1. Click Help (?), then proceed to the Search tab.
2. Select Contact Us and pick Ask about something else.
3. Enter your concern using simple phrases and keywords, then hit Continue.
4. Choose how you would kike to connect with an expert: Start a chat or Get a callback.

Please also observe their support hours to ensure you can get in touch with them.

On the other hand, you can scan this material for guidance on scheduling and managing vendor payments: Learn about QuickBooks Bill Pay for QuickBooks Online.

You may return to this thread anytime if you have other questions about modifying vendor information in QuickBooks Online. We're always here to help.