Hello, I am considering buying the new version 6 of Lightroom for desktop installation, not the cloud one. I would like to know on how many machines I can install and if the machines can be both Windows and Mac. Thanks.
You can install on as many machines as you like. The license agreement holds you to only having two of the installations activated.
I have yet to find a link for the non-CC purchase option, so I cannot say whether or not you get both platforms with the same license. If the purchase selections do not require you to specify a platform then it is likely that it applies to both.