Is Multiplicity build on .Net and if so what is the recommended version of .Net that needs to be installed?
Other than for initial activation, no, Multiplicity (MP) does not use any .Net at all.
Is this the 1st time you are using MP... or no, you have been using it for a long time and this is just now starting to happen?
What OS's?
If you do a clean boot on each PC, does it still happen?
https://support.stardock.com/space/SS/1346601039/Multiplicity+Clean+Boot
Sean Drohan
Stardock Product Lifecycle Manager