This problem mostly occurs after you reload the system, because of the problems in the store area. The solution here is to clear the data and get it again.

Thank you to Josh from wings mills, because this method is provided by him. The original address is here: https://discussions.apple.com/message/23544639#23544639

No nonsense, just look at the steps

1) Exit app store

2) Open the activity monitor and search for “store”. Then force the following two processes to terminate:

A) com.apple.appstore .Plugin…；
B) storeagent,

3) Open the terminal, input the following command and execute it:

rm ~/Library/Preferences/ com.apple.appstore .plist

rm ~/Library/Preferences/ com.apple.storeagent .plist

rm -rf ~/Library/Preferences/ByHost/*

Note that the above three commands are executed one by one.

4) Open the app store again and everything is OK.

What if it’s not normal?Hammer it, of course, I will not be responsible for smashing, you have to buy again.