Info asked:

1. Windows10, version 20H2, build 19042.804
2. Fences: 3.09.11
3. DeskScape: 8.51

Deskscape.dll                  2016/03/29 14:47:14
Deskscapes.dll                   2014/03/10 15:45:52
DreamControl32.dll                 2014/03/10 15:45:42
DeskscapesConfig.exe                  2016/03/16 14:37:48
UI\Deskscape.dll                2015/09/09 15:38:38
UI\DeskscapesVideo.dll         2014/03/10 15:45:54
DreamTasks.exe                   2014/03/10 15:45:58
DeskscapesVideo.dll              2014/03/10 15:45:22

DeskScapes appears to be activated on this PC
DeskScapes engine appears to be running

4. (BenQ GL2450H) 1 is attached to NVIDIA GeForce GTX 1070
resolution: 1920x1080

Another weird thing is: I can't seem to install new downloads from Stardock.
I get the message that my installation is not permitted because of system limitations.
I can install any other program, but not the ones from Stardock, so it's not because I can't install from outside Microsoft Store.

I wish I could. 
Like I said my system won't install the newest version of DeskScapes.

I can install any other program, but when I try installing newest version of DeskScapes it says:
This operation has been cancelled due to restrictions in effect on this computer. please contact your system administrator.

Please note I ONLY have this problem with Stardock software.
I can install any program I just download without this problem. It doesn't seem to be a problem on my computer.

Maybe it's my communication?
I don't have a problem with my key or with activation
I don't have a problem installing software in general. I can install any downloaded program I want (just tried it)

I have a problem with the downloaded software from Stardock, I can download it perfectly but I can't seem to install it.
When I try I get the error:
"This operation has been cancelled due to restrictions in effect on this computer. please contact your system administrator."

It doesn't matter with what browser I download the file (I used Fireworks, I.E., Opera, and Edge so far). It downloads great, but when I try install it, the .exe doesn't work and the message above shows up.
I tried installing it as administrator, I changed the properties on the file so any user is owner, nothing helps.

So it's not the activation (I can't even get that far), it's the installation that doesn't seem to work.

Sorry to bother you so much, but I really don't know how to make this work.

Hello Basj,

I had to turn on windows defender on my computer to adjust all options in both links you posted for me.
I'm sorry to say it didn't help.
I whitelisted the map I specially created and put the files there, but it still gives me the same message.

I turned windows defender off again (my computer is protected by third party software).
The weird part is I can install anything I want, just not the downloaded files from Stardock.
Isn't there another downloadfile I can use that does work?

Btw: when I try to upgrade through object desktop I get the same message and when I close it object desktop gives me error code 5. Does that tell you anything?

thank you!

Thank you Sean, that solved it.
I could install it !!

And that upgrade to deskscape 10 solved my icon problem too, like Basj said.

Thank you Sean and Basj for your time and patience