Hi,
I wont be using Windows 10 simultaniously (i mean, i wont have 2 VMs running at the same time).
But i need to have different development environments.
Licensing wise for Microsoft you are talking about two machines.
It really does not matter that you are not running both at the same time.
What might work however is having a base disk and two snapshot trees.. once has development environment ABC and the other one has dev environment DEF.
I'm a developer myself and personally I just got a whole range of VMs, I do not re-use the same license. Nor do I have big snapshot trees (while OK for testing for development I don't like that much as it is too fragile, best practice is to close snapshots ASAP)
If you're a developer you might also want to look into the special programs that MS has for developers.
Like Microsoft Action Pack or Microsoft DreamSpark/ BizSpark.
For testing you can also use 90 day versions of MS Windows.
Edit:
PS: On terms of use on this forum when signing up, we all agreed on not participating in breaking licenses so I cannot give you advice on how-to re-use the same Windows VM without having to re-activate.
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Wil