It would be instant upon selecting a shadow.

Are you using any other software, such as WindowBlinds? If so, you wouldn't see any shadow because WindowBlinds is currently skinning/shadowing applications.

Tried another OS. Windows 8.1

still nothing - does not work here either ? 

Only using deskscapes.  No Blinds or other at the moment.

Have the testers tried it on Windows 8.1 NOT 8.1.1 + ?

Would a Windows update block ShadowFX from running?

Have the testers tried it on Server 2012 ?

Just saying... it's not working 

Thanks for the reply.  I have been using Stardock's unique and awesome software for years.

My experience with them has always been good, however, issues do happen.  Launch8 could use some work (icons show incorrectly when an app is a shortcut) Launch8 icons could use some animation other than hard icons) Early versions of WindowBlinds, years ago, caused some problems but it has much improved over the years.  Still, Blinds themes do not respond well to systemic changes like titlebar resizing or font alterations.  Décor 8's original setup gets altered by the changes in Windows from 8 to 8.1.  There are conflicts between Stardock software themselves.  Like Blinds and ShadowFX or Décor 8 and Deskscapes in Windows 8.0 show desktop wallpaper (Décor 8 cannot show Deskscapes videos) 

Deskscapes is the only software on the planet that runs video animations other than gifs on the Windows 8.1 start screens. 

My systems are defaulted and tested with a blank installed programs list and as such do not require support resolution.

For 5 bucks, it's no biggie.  Perhaps, a version higher than 1.0 will do better.

BTW, I really like the new Stardock de-activate license option.  My hobby is to set up clean systems and often require re installs again and again.

Thanks