On Windows 10 if you right click on your taskbar and tick Show Task View button it enables Task Views icon on bottom left, next to Start button.
With that you can arrange your open programs to show in different task view, by default there's three of them.
How do you select in which Task View to load startup programs you have in your Task Scheduler?
E.g. I want to startup Mozilla Firefox on Task View 1, but Thunderbird in Task View 2 on Windows system boot?
You can't specify which virtual desktop programs open on by default in Windows 10 but you could use a third party application like vdesk
For your example you could write a batch file
vdesk 1 firefox.exe
vdesk 2 thunderbird.exe
Running this batch file will open the specified programs on the virtual desktop you define.
You could schedule this batch file to run at logon using task scheduler or add it to one of the various startup locations as described in the link.
You can download and use the free AutoIT application and utilize the Send() and Run() functions to emulate the correlated key strokes to execute specific programs in particular virtual desktops via the Task View Windows 10 functionality.
Since you say "by default there's three of them", I tested and based the below AutoIT sample script with that being the case on my system creating three Virtual Desktops (below screen shot).
You can simply use this logic and compile it to an executable file and then that executable file can be run at user login after ensuring the desktop is full loaded and the three Virtual Desktops exist.
You do not need to install AutoIT on any Windows machines the compiled executable executes by the way. I never install AutoIT and always use the portable version. The compiled executable files just run when executed on other systems with nothing else being needed typically.
Send("#{TAB}")
Sleep(200)
Send("^#{LEFT 3}")
Sleep(200)
Send("{ENTER}")
Sleep(200)
Run("C:\Program Files (x86)\Mozilla Firefox\firefox.exe")
Sleep(2000)
Send("#{TAB}")
Sleep(200)
Send("^#{LEFT 3}")
Sleep(200)
Send("^#{RIGHT 1}")
Sleep(200)
Send("{ENTER}")
Sleep(200)
Run("C:\Program Files (x86)\Mozilla Thunderbird\thunderbird.exe")
Sleep(1000)
See the screen shot with some notes on the logic but it's simply emulating key strokes that would be pressed when three virtual desktops exist already and ensures it's on Task View 1 and opens the program you need it to open there and then it ensures it's on Task View 2 and opens the program you need it to open there and it's really as simple as that. I tested with Outlook rather than Thunderbird so that's why you see Outlook in the screen shot but not in the script logic so just change that accordingly for each run function for you need.
