Same behavior for me since a few months. I am using Opera as my primary browser on both PC and cellphone since 2010, but nowadays because of my company SSO policy, I need to open local files and links in other apps in a different browser. Opera keeps making itself the default browser around once or twice every week and I need to go to Windows Default Apps and reset the settings over and over. Also, I am not sure what is the deal with frequent popups from Windows about allowing Opera to give access to Public/Private network. No other browser requires any such accesses. The only way forward I see at this point to open links in different browser for sure is to delete Opera from my PC.

I tried uninstalling Opera and reinstalled it with 'Make Opera your default browser' deselected, but the moment it got installed, it was the default browser again. I didn't delete user data at the time of uninstalling but the way Opera is behaving these days, not sure even that is going to help it.

Same behavior for me since a few months. I am using Opera as my primary browser on both PC and cellphone since 2010, but nowadays because of my company SSO policy, I need to open local files and links in other apps in a different browser. Opera keeps making itself the default browser around once or twice every week and I need to go to Windows Default Apps and reset the settings over and over. Also, I am not sure what is the deal with frequent popups from Windows about allowing Opera to give access to Public/Private network. No other browser requires any such accesses. The only way forward I see at this point to open links in different browser for sure is to delete Opera from my PC.

I tried uninstalling Opera and reinstalled it with 'Make Opera your default browser' deselected, but the moment it got installed, it was the default browser again. I didn't delete user data at the time of uninstalling but the way Opera is behaving these days, not sure even that is going to help it.

When I tried to open a PDF file stored on my computer in Opera for Windows, the browser returned error message: "Your file was not found. It may have been moved or deleted." My first thought was that the file is corrupted, but for some reason I tried to open it in Google Chrome and it opened the file. After some trial and error, I found that if I remove the pound (#) character from the file name, Opera has no problem opening the PDF file. Is this a known issue? Is it possible to handle file names with pound character in same way as other browsers do?