What is this large clickable question mark in Finder window?

All of my Finder windows show this big huge question mark, it doesn't matter which drive or directory I'm in. If I click on the question mark, it says, "The item can't be found". What is this image supposed to be, and how do I fix the error?

You probably dragged/dropped an application or any other file there, and deleted it in the meantime.

To find out what the item was, right-click the toolbar and select Icons & Labels to display toolbar labels. It should display the file name of the document or application you put there.

To find out the exact file path, open Terminal and enter the following, substituting name by whatever was displayed as label in the previous step:

defaults read com.apple.Finder | grep "name"

It will look somewhat like this:

$ defaults read com.apple.Finder | grep "LaunchBar"
"_CFURLString" = "file:/localhost/Users/danielbeck/Applications/LaunchBar.app";

To get rid of the toolbar item, just right-click it and select Remove Item, or hold Cmd and drag it from the toolbar.

I had the same issue for months. With the above answers I could fix it in two steps.

Step 1. Right-click on the Toolbar and select Icon & Text Then, it shows the name of the file or application for that Question Mark.

Step 2. Command + Drag the Question Mark out of the toolbar to remove it.

Now it looks like you need to hold: option + command and click; in order to drag it off of the finder window.