Yosemite App Store stuck checking for updates

These instructions must be carried out as an administrator. If you have only one user account, you are the administrator.

Launch the Console application in any of the following ways:

☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)

☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.

☞ Open LaunchPad and start typing the name.

Select

/var/log ▹ appstore.log

from the hierarchical list on the left. If you don't see that list, select

View ▹ Show Log List

from the menu bar.

Each message in the log begins with the date and time when it was entered. Select the messages from the last installation or update attempt, starting from the time when you initiated it. If you're not sure when that was, click the Clear Display button in the toolbar of the Console window and then try the installation again.

Copy the messages to the Clipboard by pressing the key combination command-C. Paste into a reply to this message (command-V).

If there are runs of repeated messages, post only one example of each. Don’t post many repetitions of the same message.

The log contains a vast amount of information, almost all of it useless for solving any particular problem. When posting a log extract, be selective. A few dozen lines are almost always more than enough.

Please don't indiscriminately dump thousands of lines from the log into this discussion.

Please don't post screenshots of log messages—post the text.

Some private information, such as your name, may appear in the log. Anonymize before posting.

When you post the log extract, you might see an error message on the web page: "You have included content in your post that is not permitted," or "The message contains invalid characters." That's a bug in the forum software. Please post the text on Pastebin, then post a link here to the page you created.