"Your browser or operating system is no longer supported" on fully patched Win 8.1

[Simon5EA2]

I'm using Windows 8.1 x64 on around 250 computers (I know that's a bad thing). They are fully up to date.

When receiving the "no longer supported" message for the first time I tried these steps in the following order:

1) Install latest Creative Cloud Desktop App > Reboot

2) Install latest Windows 8.1 updates (Recommended & Optional) > Reboot

3) Added DefaultSecureProtocols subkey in registry as recommended by our reseller > Reboot (but https://helpx.adobe.com/x-productkb/global/update-operating-system-and-browser.htm this only works/is only needed in Windows 7)

4) Installed the latest version of IE11 manually to be completely on the safe side > Reboot (https://www.microsoft.com/de-de/download/details.aspx?id=41628)

5) Added Registry keys to explicitly choose TLS version for every process > Reboot (https://helpx.adobe.com/de/x-productkb/multi/eol-tls-support.html)

After all of this I still get the same "usupported" error message when trying to log into an application with my Adobe ID (teams based licensing).

If you are missing any information needed to resolve this issue, please tell me how to gather it. I am happy to provide you with anything that helps.

[Test Screen Name]

Windows 8.1 EOL was a few months ago. But Adobe stopped supporting it before that. HOWEVER, this sounds like it may be related to the TLS issue - not sure, please share a screen shot, you haven't told us the full wording.