I don't really see much different between 36 and current besides colors and a few borders, which is why I asked.

I wonder if you have some group policies set for Chrome. https://stackoverflow.com/questions/26997549/google-chrome-this-setting-is-enforced-by-your-administrator for example.

But, also see https://www.google.com/search?q=chrome+settings+security+locked+by+administrator. If you didn't set a group policy on purpose and no one else did, you might have malware on your computer.

I dragged IDMGCExt.crx from IDM's installation directory into Opera to install the extension. IDM wasn't installing it in Opera for me, so I looked up how to do it and that's what I found. It's just called "IDM Integration Module" in opera://extensions.

You could hit ctrl + shift + i to load developer tools for the page and switch to the console to see if there are any errors for the IDM extension. Or, you could switch to the network tab, check "disable cache", reload the page and click one of the links to download and then check the headers of the download to check the content-type and content-disposition headers to make sure they're correct. Or, if you at least see what the headers are, maybe you can recreate the issue on a test site or something.

Can you download Opera 63, launch it, click "options" and do a standalone installation to a folder and test things there to confirm that 63 still works fine?

@blankoambit Which one worked? The flag or the extension with the string I mentioned?

You can test in Vivaldi too. If it also doesn't play the videos, it's probably an issue with how Vivaldi and Opera use the Windows Media Foundation to play proprietary media.

Also, even though I didn't need to use it, try opera://flags/#chromium-ua-compatibility to see if it helps you. If it doesn't, turn that off and use https://addons.opera.com/en/extensions/details/user-agent-switcher-5/ to set a custom UA string of exactly Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/77.0.3865.120 Safari/537.36 to see if it makes a difference.

Maybe it's a Win7-only issue though, so hopefully someone else can test too.

It might be something outside Opera like security software that's interfering in some way.

@genegold said in Opera 64 "Save as" opening instead of Internet Download Mgr:

Each file is different, but examples are not something I'd want to post on a public site.

You can pm me a link if you want. There's nothing that's going to bother/shock me and I don't judge.

You can also hit ctrl + shift + i to load developer tools and look in the console to see if there are any errors.

What does opera://media-internals say after trying to play the video?