In OS X Mavericks, Kotoeri uses the Latin keyboard layout at the prompts listed above when typing Japanese text. This causes differences in the keyboard layout when multiple languages are enabled as Input Sources. For example, if Kotoeri and French are both enabled as Input Sources, a Japanese keyboard registers the keypress of a “Q” key as an “A” instead. 

To change this behavior, disable any additional languages besides Japanese from the Input Sources tab of Keyboard preferences in System Preferences.

 Incorrect Date and Time settings

The Mac App Store relies on having the correct Date and Time settings for authentication purposes. Check to see if the Date and Time settings are correct by taking the following steps:

1. Click on the Apple () in the Menubar and choose System Preferences.
2. Select the Date & Time pane.
3. Ensure that "Set date and time automatically:" is selected, and that the chosen server is set to your region.
   For example, in North America it should be set to "Apple Americas/U.S. (time.apple.com)".
4. Verify that the correct date and time are displayed in this preference pane.
5. Choose the Time Zone tab.
6. Ensure that the correct Time Zone is selected.

Missing Serial Number

The system serial number is used for authentication purposes. If the serial number is not displayed in About This Mac, the Mac App Store cannot authenticate the connection.

1. Click on the Apple () in the Menubar and choose About This Mac.
2. Click on the Version number under OS X and it will change to a Build number.
3. Click on the Build number under OS X and it will change to the Serial number.
4. If no serial number is displayed, contact AppleCare for further assistance.

Invalid or incorrect Network Preferences 

Creating a new Network Location can assist in isolating potential Network Preference issues. 

• To create a new network location, see Using A Network Location.

Invalid or incorrect Certificates

Use the following steps to reset the cache of accepted certificates.

1. Open the Finder.
2. Choose Go to Folder... from the Go menu.
3. Type: /var/db/crls/
4. Click Go.
5. Delete crlcache.db and ocspcache.db by dragging these files to the Trash.
6. Enter an administrator password if you are prompted.
7. Restart the system and test for the issue.

If the issue persists, try editing your Keychain.

The Keychain holds passwords and certificates used to create authenticated connections from apps such as Mac App Store.

1. Open Keychain Access located in /Applications/Utilities/
2. Select Certificates from the left hand column under Category
3. Type Class into the search field in the top right corner of the Keychain Access window and press return.
4. Look through the list of results for any certificates that have a blue + over the icon.
5. Double-click on a certificate that has the blue + over the icon to ‘Get info’ on the certificate.
6. Click the disclosure triangle to the left of the word Trust to reveal the certificates permissions.
7. Change When using this certificate: from ‘Use System Defaults’ to ‘No Value Specified’ then close the window.
8. Confirm the Administrator password in the window that will appear.
9. Double-click on the same certificate that was opened in step 5.
10. Again Click the disclosure triangle to the left of the word Trust to reveal the certificates permissions.
11. Change When using this certificate: from ‘No Value Specified’ to ‘Use System Defaults’ then close the window.
12. Again confirm the Administrator password in the window that will appear.
13. Repeat steps 5 through 12 for any certificates that have a blue + over the icon. (Generally there are only one or two that will need to be edited.)
14. Restart the system and test for the issue.

Important: If the certificates do not allow themselves to be modified as is needed in steps 5 through 11, please perform a standard reinstallation of OS X then attempt these steps again.

Where did my files go?

You may be asked to create a new user during installation if the OS X installation process is interrupted. For example, if you forced the computer to power off before installation was complete.

If you create and log in as a new user, you won't see your original files and your desktop picture and other settings may be different. This is because the files and folders you are looking for are in the home folder of your original user account. If this happens, just log out of the new user you created, and log into your original user:  

• From the Apple menu () choose Log Out. Then, select your original user account from the login window to log back in using your original user name and password.

If you want to automatically log into your original user account every time you start up your Mac, follow these steps:

1. Open System Preferences from the Apple menu ().
2. Click Users & Groups
3. Click the lock in the lower left corner of the Users & Groups window.
4. Enter an administrator user name and password.
5. Click the Login Options button.
6. Select your original user account name from the "Automatic login:" pop-up menu.
7. Close the System Preferences window to save your changes.

Verify that you are now able to see your original home folder and documents. You can then remove the temporary user account if needed. Make sure you haven’t left any files in the account’s home folder before you delete it.

If you don't see your original user account

If you can't log into an account that existed before upgrading, use the following steps to see your original user accounts.

1. When requested, enter a new temporary user name and password that you will remember 
   Note: This account name needs to be different from any others already stored on this computer.
2. If required, log in using the temporary user account you just created.
3. From the Apple menu () choose System Preferences, then click Users & Groups.
4. Click the lock icon in the lower left corner of the Users & Groups window. Then, enter the password of the temporary user you created.
5. Select your original user account from the Other Users list.
6. Make sure Allow user to administrate this computer is selected for your original user account.
7. From the Apple menu () choose Log out.
8. Log back in using your original user name and password.

Verify that you are now able to see your original home folder and documents. You can then remove the temporary user account if needed. Make sure you haven’t left any files in the account’s home folder before you delete it.

When you're using these devices together, plug them directly into the Mac's USB ports instead of the keyboard. This prevents the low alert from appearing. You can also plug your devices into a powered USB hub to avoid this message.

Alternatively, simply disconnect the Apple USB SuperDrive from the computer while the USB devices are plugged into the keyboard.  

This message can appear if the date and time aren't set correctly on your computer. Use these steps to check your date and time, then try installation again. 

Check your Date & Time System Preference by following these steps:

1. Quit the OS X Mavericks installer.
2. Choose "System Preferences" from the Apple menu ().
3. Click the "Date & Time" icon in the System Preferences window.
4. Click the "Date & Time" tab in the System Preferences pane that appears.
5. If the padlock in the lower left is locked, click it and enter an administrator name and pasword when prompted.
6. Make sure the "Set date and time automatically" checkbox is selected and the appropriate region is chosen in the field to the right of the checkbox.
   Alternatively, manually set the date and time to an accurate setting (for example, the date should be set later than Oct 1, 2013).

Re-open the Install OS X Mavericks app (located in the Applications folder) and proceed with installation.

Use these steps to update iBooks and migrate your remaining books.

1. Begin by updating to iBooks 1.0.1. You can install this update from the Updates tab of the Mac App Store, or by choosing Software Update from the Apple menu ().
2. Once iBooks has been updated to iBooks 1.0.1 re-migrate your books by selecting File > Move books from iTunes.

This moves any additional PDFs or books from iTunes that weren't previously migrated.