@DanielEKFA First of all the value of prefvmx.defaultVMPath is dynamic, not static and is changed automatically through though the GUI when one uses the available controls while saving a VM when it's created whether to the default location or the last location saved if other then the default and this value is changed each time one chooses a different location. So there really is no need to manually set the value of prefvmx.defaultVMPath since it's set/updated automatically through the GUI and is a dynamic not static value!
(Strictly for the sake of argument, the exception might be in a commercial environment where the Administrator might what it to initially open to other then the default location however again the value is dynamic not static and once a user chooses to save to a different location they're taken to the last location saved, not the default or one initially set!)
Secondly, if you had read and fully comprehended this thread you'd know it was more about the default location of the Boot Camp Virtual Machine and its location is hard coded, cannot be changed and has absolutely nothing whatsoever to do with whatever value prefvmx.defaultVMPath is set to!
Thirdly, asking the question "Why do you not want to leave the Boot Camp partition in its default location?" IMO was a valid question and generally speaking there is nothing wrong with asking why someone wants to do something as it can often help garner information that may be useful to helping the user resolve the issue. Which in part it did in this particular case!
Since this thread was primarily a discussion between OxkAMam and myself and two of my replies were marked helpful and the question itself was marked as answered your inflammatory comments are as useful as sakibpavel's reply was, worthless and totally irrelevant to the actual discussion at hand as was the rest of what you said was as well!