Last Updated on April 12, 2026
When it comes to opening files on your computer, Windows does this based on the type of file you are trying to open. If Windows didn’t do this, then you would somehow have to manually choose an app to open a file each time. You probably also noticed that your files have icons that match the program used to open them.
I’m sure you have noticed that at the end of your files there is usually a dot or period and then 3 or 4 letters or numbers such as Report.xlsx. This is what is known as a file extension that is used for Windows file associations. Windows uses file associations to determine what program to use to open a certain type of file. For example, Windows will know that resume.docx is to be opened using Microsoft Word since .docx is the file extension for Word.
There may come a time when you want to use a different program to open a certain type of file or you may also have a type of file that Windows doesn’t know how to open. If that’s the case then you can change the file association or in other words, change the program Windows uses to open that type of file. This is not the same as changing the file extension for the file itself because generally you do not want to do that because you will most likely not be able to open the file afterwards. While some formats are interchangeable, like renaming a .jpeg to .jpg, changing an extension manually usually makes the file unreadable to the system.
The easiest way to accomplish this is to open File Explorer and browse to where your file is located. Then you can right click the file and choose Open With and then choose a program from the list.
If the program is not listed there, then you can click on Choose another app instead.
Next you will be presented with an Open With dialog box.
You can then choose another program from the list or scroll down to where it says Choose an app on your PC and browse to the location of that program on your computer. In the modern Windows interface, you will see two options: “Just once” and “Always.” Selecting “Always” sets that application as the new default for every file with that extension. If you don’t see the app you want, click “Choose an app on your PC” to manually locate the .exe file in your Program Files folder. So you want to make sure you choose a program that can actually open that file type. If you mess this up or change your mind, you can come back to any file with that extension and redo the process and change the associated program.
Managing Associations via Windows Settings
If you want to see a full list of your file types in one place, you can manage them globally:
- Press Windows Key + I to open Settings.
- Go to Apps > Default Apps.
- Scroll to the bottom and click “Choose defaults by file type.”
- Here you can see a giant alphabetical list of every extension and exactly which program is assigned to it.
If you are looking for a good app to help you find your files quickly so you can manage their extensions, then you may want to check out Listary File Search. It’s a powerful tool that integrates directly into File Explorer to make finding deep-seated files instantaneous.
Understanding file associations is the key to a customized Windows experience. Whether you prefer a third-party media player over the built-in Windows options or a specialized code editor for text files, knowing how to toggle these associations ensures your computer always uses the tool you prefer. Just remember: always change the association, never the extension name itself!
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