If you know the ldraw folderis going to be changed by other software, you should not put it in 'program files' but in some user location (e.g. d:\LDRaw) or inside c:\programData, but you might need to set general write access to it's folder (programData is read only by default to other users).
In short anything you put in program files is expected to be static after installation by recent windows versions. And programData is for (dynamic) stuff shared between multiple programs. And the users/<name> tree is for user specific stuff (config per user etc).
In short anything you put in program files is expected to be static after installation by recent windows versions. And programData is for (dynamic) stuff shared between multiple programs. And the users/<name> tree is for user specific stuff (config per user etc).