Hi,

To know more about your concern, kindly answer the questions below:

• Have you already tried clearing your browser's cache?

• Have you tried to use a different user profile and check if the issue still persists?

• Do the same issue happen when accessing from a different browser or computer?

For the meantime, you may follow suggested steps given by Jordan Dom from this link and check if it makes any difference.

Update us with the result.

Yes, I have cleared my browser cache for multiple browsers (Google Chrome, Microsoft Edge, iOS Safari) on multiple devices on multiple internet networks.  The issue persists; I am able to delete past search history, but I do not see an option to turn off search history going forward. I only have one Microsoft Live account.  I have changed my default search engine to another provider while waiting for this to be fixed. Thank you.

I can think of two solutions (which you might not like):

1. Use another browser than Edge or don't used Bing.
2. Don't use a Microsoft account, which is where your data is stored.
   See the article How to Revert Your Windows 10 Account to a Local One.

While you are about it, you might also disable the biggest threat to your privacy : Cortana (See this article). Point 2 above will also block Cortana.

As another remark, third-party apps are always safe : If you don't use Windows 10 apps for browsing, search and mail, no history is kept.