How do I undo "Always open with" option in Windows 10

Are you saying that the option to reset the file type association in Settings is missing on your PC? The button should be under Settings > Apps > Default apps. Clicking Reset should revert back all of the file association to default.

If this is the case, you can try creating a new user account and then check the default app for the PUP file type. A new user account will have a default configuration. Therefore, you can download the PUP file on the new user account to figure out the default app and then switch back to your main account to modify the default app configuration. Check this link for the steps on how to create a user account in Windows 10.

Let me know if you need further assistance.

Hello! I'm sorry to say that what you replied with, won't help me in any way because the default/reset option is not available (please add it <3) after you've saved it to something else. I downloaded a .PUP file from the internet, placed it to my desktop, right clicked on it and clicked on "Open in." and then I selected "Internet Explorer" (and I also clicked on the save checkmark thing). Now, how am I supposed to know what type of app it was originally opened in, there are tons of apps! I think the .PUP file is originally opened in an app which is not downloaded on my PC, but Windows supports that type of app, for example, like the 7z-zip files, but you don't have to download something (just a theory). Please help me.

I think I have an idea of how to solve my problem and how to find the correct app to open in. Go and download the same file I just did at https://www.playstation.com/en-us/support/system-updates/ps3/ (If you don’t want to click on the link, go to your browser and type in “PS3 System Software Update – Latest Version 4.82 – PlayStation” and then, click on the first link). It’s a firmware for PS3 I downloaded officially from PlayStation, so you know it’s legit. After It is done downloading, open it and try to find what type of program/app it is by looking at the layout of the file when it’s open.)

Please respond and help me.

Hi Sulejman,

I would like to know more about the solution you mentioned in your post. Can you tell me how you were able to resolve the issue before? This is so we can avoid repeats with the troubleshooting steps that we're going to provide you.

If you're planning to switch the program that opens PUP files, you can do so by following these steps:

1. Right-click a PUP file.
2. Select Open with > Choose another app.
3. Select the desired program to open PUP files.
4. Make sure to select the Always use this app to open .pup files check box.
5. Click OK.

Let me know the results.