I thought you wanted to remove a specific url and not all urls of a specific domain.

You thought correct. I want to prevent certain specific URLs from being predicted when I type something in the address bar. The problem is that when I delete that specific URL from my history, it's still predicted when I type. When i uncheck the option to use opera's prediction service in the settings, it still predicts the URLs I've visited, and continues to predict new URLs (but only after I've visited them once). So far, the only way I've found to delete the saved addresses is to clear all browsing history. After doing that, the prediction service continues to save and predict all the URLs I type in the address bar.

The prediction service is supposed to save me time and effort. Currently, when I want to visit Youtube, opera predicts "youtube.com/user/someyoutubechannel/videos", and i have to write the whole "youtube.com" instead of just "y" in order to visit the front page of Youtube. It's annoying.

I think I'll start a new discussion, because my question/problem was a bit vague in this one, and it's starting to get cluttered. Thank you for your answers

  I still don't know how to delete just one of the URLs though.

Go to History, put the mouse cursor over the url you want to delete and click on the "X" on the right.

Even if I delete that one URL from all of my history (it appears several times), the URL is still predicted when I type in the address bar. Maybe I need to delete all of the "sub-addresses" also (like www.url.com/subpage in addition to just www.url.com), but that would just be too much work.

I thought you wanted to remove a specific url and not all urls of a specific domain.

You must be seeing Google's Search prediction working. This is not related to that setting afaik.

I don't think so, because it never predicts anything when I type in addresses i have never previously visited.

I still don't know how to delete just one of the URLs though.

Go to History, put the mouse cursor over the url you want to delete and click on the "X" on the right.

Even if I delete that one URL from all of my history (it appears several times), the URL is still predicted when I type in the address bar. Maybe I need to delete all of the "sub-addresses" also (like www.url.com/subpage in addition to just www.url.com), but that would just be too much work.

At least here if i remove something from history, it no longer appears on address bar.

Just discovered that unchecking the "Use a prediction service to help complete searches and URLs typed in the address bar" doesn't work. I tried restarting opera, but it still doesn't work. I tried typing in addresses I have never visited before, but the prediction service still saves them.

You must be seeing Google's Search prediction working. This is not related to that setting afaik.

I still don't know how to delete just one of the URLs though.

Go to History, put the mouse cursor over the url you want to delete and click on the "X" on the right.