Incognito Browsing
Sometimes referred to as Private Browsing, Incognito mode is an Internet browser setting that prevents browsing history from being stored. Normally, when you visit any web page, any text, pictures, and cookies required by the page are stored locally on your computer. Incognito mode forgets this data when you close the browser window, or doesn't store it at all.
Why use an Incognito Window?
When a user runs into a problem that you cannot recreate, using an Incognito window will use a browser's default settings with no extensions. This will help rule out if it is an extension causing the issue to occur.
For more information on Incognito and private browsing: