BLANK Cloud Screen http://forums.adobe.com/message/5484303 may help
-and step by step http://forums.adobe.com/thread/1440508?tstart=0
A chat session where an agent may remotely look inside your computer may help
Creative Cloud chat support (all Creative Cloud customer service issues)
thank you very much!
It may be your Network Card Driver is incompatible with the Creative Cloud App. In My case the Creative Cloud App would log in but then only show a blank rectangle labeled "Creative Cloud. I had two multiple hour sessions with Adobe Tech Support trying all the stuff above while controlling my computer remotely to no avail.
I uninstalled my Windows 7 PCIe Realtek GBE Driver and installed the Realtek Windows 8.1 PCIe GBE Family Driver fixed everything, the flashing hourglass -gone, the Libraries module flashing -gone, Creative Cloud blank -now working. I was running Windows 7 Pro (64 bit) when this problem started month ago when I upgraded to Photoshop CC 2015 and the most recent version of CC app, I upgraded to Windows 10 pro (64 bit). The Windows 10 installed a NIC driver that slowed my Gigabit Ethernet card to 100mbs, so I downgraded to Windows 7 driver so problem persisted until I installed the Windows 8.1 drivers.
I don't know if this only applies to just the Windows 7 RealteK PCIe GBE Driver or if it applies to other operating systems and different ethernet chip manufacturers, but it does give you another avenue to explore.