This update will not install

What happens when you try to install it? Be as specific as possible.

If you have more than one user account, these instructions must be carried out as an 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. Click Utilities, then Console in the icon grid.

Select "/var/log/install.log" from the file list. Post 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, start over and note the time.

Post the log text, please, not a screenshot. If there are runs of repeated messages, post only one example of each. Don’t post many repetitions of the same message.

When posting a log extract, be selective. Don't post more than is requested.

Please do not indiscriminately dump thousands of lines from the log into a message.

Important: Some private information, such as your name, may appear in the log. Edit it out by search-and-replace in a text editor before posting.

Launch the Terminal 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. Click Utilities, then Terminal in the icon grid.

Drag or copy — do not type — the following line into the Terminal window, then press return:

sudo chflags -R nouchg,nouappnd $TMPDIR.. ; sudo chown -R $UID:20$_ ; chmod -R -N $_ 2> /dev/null

Be sure to select the whole line by triple-clicking anywhere in it. You'll be prompted for your login password, which won't be displayed when you type it. You may get a one-time warning not to screw up. You don't need to post the warning. If you don’t have a login password, you’ll need to set one before you can run the command.

The command may take a noticeable amount of time to run. Wait for a new line ending in a dollar sign (“$”) to appear, then quit Terminal. Try the installation again.

Let's try again to get some information from the installer log. Display it as before, but this time click the Clear Display button in the toolbar of the Console window. Then try the update again. Post the messages that appear.