"Why can't I install Lightroom to a custom location through the Creative Cloud?
Lightroom must be installed to your local drive and can't be installed to custom location like other Creative Cloud apps. Lightroom always installs to the default location and disregards any preference you select for a custom location. This behavior is as designed."http://helpx.adobe.com/lightroom/kb/lightroom-creative-cloud-faq.html#id_95665
That's one of the reasons I dislike Adobe, they tend to make things just as they think it should be and do not let the customer make his own choice. It is simply ridiculous to only let LR install on C:\. Instead of saying "This behavior is as designed" they better should have written "We just forgot to let it install on other partions/drives instead of the default location." I hope they will fix this error soon.
I like some of their products but I do not like the companies arrogance. Still hoping this will change some day (with hopefully some serious competitors showing up soon.)