It doesn't matter if I reinstall everything including extensions, use it without extensions or switch languages.
But it seems strange to me, that the installer always offers to upgrade my opera installation, as If he would not get that the current installed version is already the highest.
If you want me to do some deep debugging suggest something to start with.
Installer
Size: 671 KB (687.600 Bytes)
Source: http://net.geo.opera.com/opera/stable/windows?http_referrer=missing_via_opera_com&utm_source=(direct)_via_opera_com&utm_medium=doc&utm_campaign=(direct)_via_opera_com