After my Dell 6420 laptop was upgraded from Window 7 to 10 by performing a full re-installation it is impossible to install Dopus. I have tried Dopus 10, 11 and 12 installers (my licence is for Dopus 11).
The error message is
Error Code: -5006 : 0x8000ffff
$18.0.329PAK @Windows 7 / Server 2008 R2 Service Pack 0 (9200)
IE Version: 9.11.14393.0
Originally I installed from my private area on a network drive. That gave the error. Then I tried from a public network drive. Then I got a completely different error: "The trust relationship between the primary domain and the trusted domain failed"
Finally, I copied the installer to my C: drive and everything went fine!
This said, it has always worked fine to install Opus (and many other programs) from that private network area before on both Win XP and 7.