[scripting] How to pass boolean values to a PowerShell script from a command prompt

You can also use 0 for False or 1 for True. It actually suggests that in the error message:

Cannot process argument transformation on parameter 'Unify'. Cannot convert value "System.String" to type "System.Boolean", parameters of this type only accept booleans or numbers, use $true, $false, 1 or 0 instead.

For more info, check out this MSDN article on Boolean Values and Operators.