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Rebuild Your Database

Outlook users

Entourage Users:

You should rebuild the database if:

  1. You have problems starting Entourage, or viewing, opening, and storing items.
  2. Items that refuse to be deleted.
  3. Need to reclaim disk space..

FAQ: “If I rebuild my Entourage database will I lose all my categories and links!”

[ANS] Not anymore with Entourage 2008!

Links don't get zapped with v.X if one is doing the Typical rebuild. (clarification provided by Entourage user, Alan)

It is recommended that you not rebuild your database as regular maintenance. Rebuilding should not be considered as a substitute for an adequate backup. You are encouraged to back up critical data on a regular basis.

Rebuilding should be avoided unless there is database corruption. Here's what Jud Spencer [one of Entourage’s developers] said on the issue:

There is a small benefit to compacting regularly. Entourage maintains internal sort tables. Those sort tables are optimized on a compact.

However, you should only choose the rebuild option if your database is damaged. Many people believe that rebuilding your database will protect you from future corruption. That just isn’t the case.


Tip: Emptying the cache does not reduce the database size itself. The database will be left with 'wasted' space in it every time you delete something. However, this is not all bad, since the wasted space is used up with new data as it is added. This way, over a period of time (assuming that you are deleting stuff as you go) the database will probably reach an optimum size, after which the stuff you delete is roughly equal to the stuff you add, and no further growth takes place.

If you need to recover the wasted space on your hard disk, you will have to do a 'typical' rebuild to compact the database. This will create a compacted version of the database without the wasted space. You will then have to manually delete the backup copies of the original database that the rebuild process creates AFTER you are happy the new one is OK.

How to Rebuild Your Database

  • As with any procedure like rebuild, it's a good idea to make a backup prior to running. Your data should not be erased, but if something fails during this process, data could be lost. To be doubly sure, duplicate your Identity folder prior to the rebuild.
    • Make a duplicate in the Finder first as additional backup. A rebuild does make a duplicate, but sometimes in the process the original and backup get merged resulting in total disaster. It's rare but it happens.
  • Locate your database. It should be in your Documents folder: Can't find your database? See tip #9
  • Find the size of your database, use Get Info (Command + I).
  • Make sure you have enough hard disk space available for twice that amount. As part of the rebuilding process, Entourage creates a second database file.
    • Your system needs a minimum of 10% free. The more space you have to rebuild the more likely your rebuild will be successful. See this article for tips.
  • Quit any applications that are running, including virus-protection applications, all Office applications, Microsoft Messenger for Mac, and Office Notifications, because they might interfere with rebuilding. How to quit Notifications.
  • If you can’t get to the rebuild screen, there could be a conflict with another application. Try restarting your computer with Shift key down to quit remaining processes. For example, "Quicken Scheduler" can interfere with the process.

  • Rebuild your database:
    • Entourage 2001 and Entourage X: Hold down the Option key and re-launch the application. In a few seconds, you'll be greeted with a dialogue box asking if you want the "Typical Rebuild" or the "Advanced Rebuild." Choose "Typical." Links don't get zapped with v.X if one is doing the Typical rebuild. (clarification provided by Entourage user, Alan)
    • Entourage 2004 & 2008: Hold down the Option key and re-launch the application. In a few seconds, you'll be greeted with the Entourage Database Utility. Select to rebuild. (Note: Compact the database (Like X's "Typical rebuild") Rebuild the database (Like X's "Advanced Rebuild")
    • Note: Verify database is not always accurate. To give your database a stress test, see this article: Is corruption hiding in your database?
  • Caution: Some of your data might be lost if you choose the Advanced Rebuild option. You should use this option only if you have already performed a typical rebuild and continue to experience problems starting Entourage or storing data.

    During the rebuild process, the old files are renamed in case for some reason the rebuild was not successful and you need to revert to the original database. After you've rebuilt your database and checked the application's performance, you can delete the old versions from your hard drive. Do not throw away these files unless you are satisfied with the rebuild.

    Old files are named:

    • Entourage 2004 & 2008: Main [Backed up date and time will be shown] e.g. Main [Backed up 1-21-2007 13.35]
    • Entourage X: "Old Database Cache" and "Old Database"
    • Entourage 2001: "Old Database Cache", "Old Database", and "Old Messages." In addition, Database (Rebuild) Cache is retained.