MSB is not displaying the expected range of dates for my device. Why are my some items missing?

Confirm that MSB is registered (check to see if it says ‘REGISTERED’ in MSB’s Preferences pane) 

If you are not seeing your recent data

MSB relies on iTunes to keep its backups current.

Check to see if iTunes is updating backups as well as  syncing media when your device is attached. If your device is running iPhone OS 3.0 or greater, check the settings to make sure the backup encryption is OFF. MSB cannot read an encrypted backup and will skip it.

To disable encryption, select your device in iTunes and make sure ‘Encrypt iPhone backup’ is not checked. The nextbackup performed will not be encrypted.

If you are using iTunes 10.5 or higher, make sure your device is not set to backup to iCloud.

iTunes Settings Tab
Make sure your iTunes settings are correct.

Then, in iTunes’ Preferences, select the Devices tab and see if the listed backup date for your device is consistent with your last sync (MSB should display the same info in the top ‘Backups’ list).

NOTE: Apple has changed the name and appearance of this tab on many occasions.

iTunes Backup Date
Compare your backups using iTunes’ preferences

If it is not current, attach your device and right-click/control-click on its name in the left column of the main iTunes window, then select Back Up from the pop-up menu that appears.

iTunes Device menu

When iTunes has successfully completed the back up, relaunch MSB.

If you are not seeing your archived data [Before version 6]

Verify that you have not inadvertently moved or renamed  the ‘MobileSyncBrowser Data’ file in your Documents folder.