Mac App Store opens to blank screen; cannot switch between menu options

Solution 1:

I killed all store* processes in Activity Monitor. Then relaunched App Store and it started working.

Solution 2:

Mine would always freeze when trying to open it, I tried killing the processes, signing out through iTunes, restarting, and nothing worked. I ended up updating the OS and iTunes through terminal and once I restarted the app store worked again!

From terminal, typing

softwareupdate -l

will give you the available updates. Then you can install them doing something similar to:

softwareupdate -i OSXUpd10.10.4-10.10.4

based off the list of available updates.

Source: http://osxdaily.com/2015/07/01/fix-frozen-app-store-updates-and-high-softwareupdated-cpu/

Solution 3:

I just had this problem, poked around online, and solved it by resetting the NVRAM. It's generally my second go-to solution if rebooting doesn't fix it.
Here are the Mavericks NVRAM reset instructions:
http://support.apple.com/kb/PH14222?viewlocale=en_US

Resetting NVRAM

  1. Shut down your Mac.
  2. Locate the following keys on the keyboard: Command (⌘), Option, P, and R.
  3. Turn on your Mac.
  4. Press and hold the Command-Option-P-R keys immediately after you hear the startup sound.
  5. Hold these keys until the computer restarts and you hear the startup sound for a second time.
  6. Release the keys.

Solution 4:

Found Safari would not open any sites, however VNC worked fine. Go to Preference, Network, advance button at bottom, then look at the DNS tab. I found both DNS Servers and Search Domains were blank. Added my DNS info and Domains to search. Started to work. :)