com.apple.Safari.SafeBrowsing.Service quit unexpectedly

Ok, but, you can just do the exercise that I suggested and then if it works import the settings back for Safari from TimeMachine from any of the proceeding days or, simply ring Apple tomorrow and ask them what the dialog box is all about and how to resolve?

Finally, the solution by "martin from" worked for me:

1. remove all history from Safari.

2. re-index spotlight (takes several hours).

No re-appearance of the pop up since then. So that's good.

Btw, it had no direct link to the 10.12.2 upgrade, at least not on client side. The pop-up started occurring while I was still with 10.12.1. And it kept coming back after I upgraded.

But I am sure that Apple did some change server-side that has led the safe browsing service to run bad. Surely somehow related to the 10.12.2 upgrade, a change to the underlying services or so. In any case, I find it poor handling of Apple to react and fix this quickly as I am sure it's just a minor glitch and quick to fix. My two cents...

Glad that has worked, however, I had in a later post explained that this did not hold and I did this:

1. Close all Safari windows then just open Safari Browser.

2. Go to History on top bar and Clear History (bottom of drop down menu).

3. Clear all cookies (Safari/preferences/privacy/manage website data/remove all).

4. Close Safari and restart Mac.

That has held ever since although, of course I do not know what Apple may have done within all this as the drama unfolded.