The monitor count of any PC is only relevant for the new 'Seamless Display' feature.  If this is not your intended use for your future extra monitors,  to connect a Primary to a Secondary's monitors, this is of no consequence. 

That said, if that is indeed your use case, that you will have a Secondary with a high monitor count that you want the Primary to use as its own with the Seamless Display feature (please don't confuse this with the normal 'Seamless' feature itself), there is no planned ala carte option for it. 

Sean Drohan
Stardock Product Lifecycle Manager

This question is not germane to the OPs initial question.  Please create a thread of your own. 

In it, please note if you have tried ensuring it is indeed set to be the Primary and if you have activated it

Sean Drohan
Stardock Product Lifecycle Manager

sdrohan, thanks for the response, but I found that a little confusing.  I am unclear on the difference between 'seamless' and 'seamless display' features.  Can you direct me to a faq (or some such) that might explain theses two features and their differences?  If I needed an expansion, the configuration would likely be something like 3 (maybe 4) computers with 6 monitors, altogether.  I would want to be able to view my main pc on all monitors at once, but be able to pull up either of the other computers on one or more monitors, as needed.  That would be the 'seamless display' feature?  Of course, I would like to be able to use the mouse/keyboard across all connected computers, but that seems more than covered by the software, already. 

I only just now realized that I misread the limitation as 5 monitors, when it is actually 5 computers.  Nevertheless, the above describes my desired outcome.  Right now, my main computer has three monitors, my secondary is connected to hdmi1 on a seperate monitor, and my tertiary display is on hdmi2 of that same monitor.  The main computer curretly has the multi-monitor app Actual Multiple Monitors installed (though I will likely switch to Display Fusion) and all computers have Microsoft Garage Mouse Without Borders.  Obviously, Multiplicity's kv features would replace Mouse w/out Borders.  Either AMM or Display Fusion will take care of expanding my multiple monitor configuration on the main computer. At that point, what I would need from Multiplicity is to be able to bring my secondary and tertiary computers up on one of the 5 (potentially 6) monitors on the main system.  Multiplicity will supply that functionality, will it not?  In general, does multiplicity leave all of the multi-monitor management for the individual systems up to either system software or other third-party software? When using the primary computer's monitor(s) to view a different computer, does it default to applying the existing display settings of that computer to the view?

I realize it may have been quicker for me just to download the trial, but trials rarely truly provide time to see if things will work out like you envision them and, besides, I don't know how long my re-configuration is going to take and don't want to set something new up before I am ready to fully configure it.  Anyway, it seems counterintiutitve to add potentially temporary software when a substantial part of my overall goal is to tidy up my systems a bit to optimize them and repurpose them for dedicated functions.

In any case, I appreciate you time and insight.

P.S.  I am abashed by my own snarkiness in the title of my initial post.  I see that you guys' response time was OUTSTANDING.  I apologize for being rude.

I dont hide well the fact that Multiplicity is my favorite product we make - it is very dear to me.  Neil (as the lead on the product) has outdone himself with MP4 (dont tell him, however, his head is big enough 😉)

Thank you for the kind words.

A legit fear of mine, so much so I want to change the name 'Seamless' to match the two-worded 'Seamless Display'.  I have a nasty habit of getting my way via nagging

Its still very early but we are working on it...

https://support.stardock.com/space/SHC/2074640390/Multiplicity+4

While Multiplicity (MP) is very much a product where you have to use it to really 'get it', this will help you better understand 'Seamless' use:

https://forums.stardock.com/501405/multiplicity-km-tips-and-tricks-for-getting-started

When utilizing 'Steamless Display' it's really no different than adding new monitors to an existing PC. 

When monitors are added to an existing PC (PC1 let's call it), they show up on the Windows Display grid:

But what if you did not have any other monitor connectors on PC1 or you had an older PC \ laptop that had a perfectly good set of monitors attached to them? That is where 'Seamless Display comes in.  When setup and connected, those Secondary monitors (PC2's) show up as connected in Windows Display on PC1.

Effectively, I have added 2 new monitors to PC1 - I can move my mouse and apps to them as if they were physically connected to PC1. 

This is where the 'monitor count' comes in for the versions that have 'Seamless Display' as an unlocked feature.  For normal 'Seamless' connections, where the mouse cursor is just handed off to the Secondary and its monitors, monitor count is irrelevant.

Hope that helps.

Sean Drohan
Stardock Product Lifecycle Manager 

I would HIGHLY recommend disabling them for any MP testing you would do.  If you do have any issues, much time could be spent (wasted) on even reaching a conclusion that they could be a cause. 

Sean Drohan
Stardock Product Lifecycle Manager

I have downloaded the Multiplicity trial and am having a very, very disappointing start to my experience with it.  I installed it on my three computers, but it will only allow me to use 2 computers (the primary and one secondary).  Even at that, the features (beyond mouse/keyboard sharing) either barely work (click and starts to process then does nothing, or starts to work but only works for a few seconds, then drops out - using other computer monitor(s) and remotely viewing another computer, in particular) or don't work at all.  Nevertheless, I was able to see how the app was meant to function and how useful it could be.  I therefore assumed that the poor and/or lacking functionality was just restrictions on the trial version, so went ahead and purchased the pro license, but that changed nothing.  On my secondary computer it continues to function only minimally and on my third computer it does not function at all (won't even let me set it up, due to 'invalid' license) and just keeps telling me I need to buy an additional license. The website says that the pro license is good for 10 computers for KM and 5 for KVM, so what's the deal?  I may need a refund, but I would much rather see this working as advertised. For years I have been using the free app Microsoft Garage Mouse Without Borders for keyboard/mouse sharing, which works very well, so I was shocked that even that basic function would not work across my devices.  I already removed other apps integral to my environment, in order to avoid conflicts with Multiplicity, so I am kinda in limbo, now. 

Also, just to note; my semi-working secondary computer still says the version installed is a trial.  I believe I read somewhere that only the primary computer requires a licensed copy of the software, which is fine, but you need to find a way to remove that label when the other computers are connected to a computer with a licensed copy.  As a consumer, when I pay for something that says it will cover all of my devices, I don't want to see the word 'trial' anywhere.

Sorry to read that.  

Multiplicity 4, as stated, is in a 'Public Beta'.  Yes, you should have the basic advertised functionality (as most all do).  However, it is expected that some will have some issues - this is why it was released at it was, to get a larger testing audience with configurations we could never hope to reproduce internally.  There never should be a case where it is tested in a production environment where 100% uptime is expected.

Knowing nothing about the PCs you have MP4 installed on (OS version, CPU, network connection), I would like to start by

• ...purging MP4 on each \ all PC,  this can be used to help facilitate the process:
  https://support.stardock.com/space/SHC/1347158073/Multiplicity+purging+and+re-installing#Obtaining-the-purge-file
• Reboot as directed after. 
• Install on the PC you want as the Primary (the controller).   YOu will be asked to activate it after the selection, please do so.
• Install on what you want to be the Secondary (only 1 PC for now).  You should NOT be asked to activate. 
• Make it a 'Seamless' connection (thus, you are able to actually physically see the PC you want to control and its monitor(s).  For more on the differences between KVM and Seamless connections, please see:
  https://support.stardock.com/space/SHC/1287815196/Multiplicity+Seamless+vs+KVM+confusion
• Make the necessary changes for the encryption key and passcode to match that of the Primary.
• Create the connection on the Primary. 

Let us know the results.

Sean Drohan
Stardock Product Lifecycle Manager