The tech giants have also added in a bit of sassy humour into their pop-ups, with one saying: "That browser is so 2008! Do you know what's new? Microsoft Edge."
Another prompt says: "'I hate saving money,' said no one ever. Microsoft Edge is the best browser for online shopping."
Unlike the old Internet Explorer browser, Edge adopts the Google-made Chromium platform. Microsoft said that makes it more streamlined and faster.
It appears people are reluctant to move across, with Edge not yet making a dent in Google Chrome's market.
Microsoft's new prompts come more than three years after the company first started testing ways to warn Windows 10 users not to install Chrome or Firefox. Those tests were never rolled out publicly, but these prompts are now starting to appear for Windows users.