You need to Clear Temp folder .
What actually happens is when you try to install an App from Adobe Creative Cloud app , first it will download compressed setup file on to Temp folder ( 0-42%) , for this it needs space ,
After 42 % , it will extract the compressed file and then install the applications like Photoshop ,Illustrator ,,,etc on to different drive as per your settings.
Once you Quit Adobe Creative Cloud app , the compressed setup will disappear from Temp folder . or you may need to clear temp folder manually again. you can skip the files which cannot be deleted while clearing Temp folder.