Go to Passwords (direct from the 3 bar menu) and delete the incorrect entry.

The incorrect entry is not there; what shows is my correct email address; moreover PASSWORD is not the issue - it is USERNAME.

Can you post a screenshot of the prompt?

I can show a screenshot, but it would expose my email address and phone number - something I'd rather avoid.

Thank you for that advice. I wrote a long reply, but lost it because of what you see in the image.

I will try to repeat, now that I have access again, the substance of the post that was lost. Although the corrupted prompt appears for various websites, the only one I am certain of is Mozilla Support, and it is now remembering the correct prompt, so not showing me usernames to choose from (and copy for you to see). As soon as get the chance to get a snip of the corrupted prompt, I'll send it here .

I can access a list of saved logins, and the corruption is not amongst them.

Progress at last : Terry, here is the screenshot you asked for.

Deleting DATA did NOT fix the problem. The attached snip shows which path I took to delete DATA.

It still seems to me that you should be able to delete that in passwords. I search for the site. Some sites have more than one log-in and I delete those I no longer want to use.

Edit: OK, you say it isn't there. I don't know where it's coming from. You could try forgetting the site (backing up any valid username and password first).

https://support.mozilla.org/en-US/kb/delete-browsing-search-download-history-firefox#w_remove-a-single-website-from-your-history

It is not just one website - that username (corrupted email address) is prompted by default for multiple sites.

Too many to forget?

I don't understand that answer, but I figure that you can help me no further to delete that corrupt entry.

I presume you are not the only helper at Mozilla Support Forum, so maybe a colleague can progress it ...

Although I tried and failed before making my post, I have since been able to 'select' the corrupted email prompt and remove it, by pressing the DEL key. The corrupted email address has NOT been prompted since I achieved that. Nor has the DIFFERENT corrupted email address been prompted by Chrome - SO FAR !

Suggestions in a login drop down list that have a key icon in front are login suggestions that you need to remove in the Password Manager.

• https://support.mozilla.org/en-US/kb/password-manager-remember-delete-edit-logins

Suggestions in a drop down list without a key symbol are autocomplete saved form data. Suggestions without a key icon are part of autocomplete saved form data that you should be able to remove by selecting this item with the cursor Down key and pressing Delete (Mac: Shift+Delete).

• https://support.mozilla.org/en-US/kb/control-whether-firefox-automatically-fills-forms

I have a similar issue. I created a new email address (DuckDuckGo) and decided to not use it, and created a second new DuckDuckGo email address instead

But whenever I am prompted to register an email address (eg to change it) I am prompted with the DuckDuckGo email address I first created.

- It is not listed in Firefox "Logins & Passwords" - I have cleared the cache - I have tried Shift+Delete when this address is prompted

Is this a Firefox or DuckDuckGo issue?

- and I have Cleared History

I had a corrupted email address being prompted in both Firefox and in Chrome - they were similar, but different corruptions. When I posted the question, selecting the corrupted entry and pressing the delete key was NOT effective, but eventually that did work. However now I have the same uncorrupted email address prompted TWICE along with my phone number. I haven't had a chance to 'test' this in Chrome, but THINK its corruption also disappeared. I am glad the corruptions are gone but am dissatisfied at having been unable to locate where the corruptions are stored.