Best practices for using Outlook .PST files on portable USB drives

You can save Microsoft Outlook email data in a .PST file to a portable USB storage drive, but make sure you understand these best practices first.

Is it possible to save Microsoft Outlook email data in a .PST file to a portable USB storage drive for use on either a laptop or desktop computer? I'm frequently asked this question by remote users who often switch between laptops and desktop PCs. The answer is yes.

A Microsoft Outlook .PST file can reside anywhere you want, and a removable USB drive is a perfectly legitimate location for it. Even though Microsoft doesn't recommend placing an Outlook .PST file on a network drive, because of the amount of network traffic that can be generated as a result, a locally mounted USB drive should be fine.

If you do decide to store Outlook email data in a .PST file on a USB drive, try to adhere to these best practices first:

  • Make sure Outlook is shut down before dismounting the drive.
    Microsoft Outlook tends to take several seconds to shut down completely. This is to ensure that everything has been closed properly within the application. It would be helpful to users if Microsoft Outlook provided a progress bar, or something similar, that could show the process of relinquishing control of the .PST file. In the absence of anything like that, however, you can wait 10 seconds and then check to see if OUTLOOK.EXE is still running in Task Manager. If it is, just wait until it vanishes and then dismount the USB drive.
  • Use a USB drive that's at least twice the size of the .PST file.
    Make sure you place the Outlook .PST file on a large enough drive to accommodate any future file size growth that the .PST may experience. If you have a 100 MB .PST file and you place it on a drive that's only 128 MB, for instance, you're likely to run out of room fairly soon, even if you have Outlook's AutoArchive feature enabled.
  • Enable Microsoft Outlook's AutoArchive to keep .PST files small.
    It makes sense to have auto-archiving enabled so that the .PST file
    More Microsoft Outlook .PST tips and resources:
    How to export .PST data to a USB memory key

    Migrating older .PST files to Microsoft Outlook 2003

    Migrate or merge Microsoft Outlook .PST files with Upstart

    A primer on .PST files

    Outlook .PST Reference Center
    doesn't grow inordinately. However, it should only be enabled on one machine (probably your desktop), so that there's one master archive. Keep in mind that if you're using the advanced indexing functions in Microsoft Outlook 2007, you may not have instant access to data in the .PST whenever you transfer it to another machine. The indexer will sense that the .PST file has changed and attempt to update itself. (To get an idea of what the indexer is up to, look at the Indexing Status window in Tools -> Instant Search.)
  • Abide by corporate email compliance and retention policies.
    Most importantly, confirm your organization's email compliance and records-retention policies regarding .PST files before saving any corporate email data to portable storage devices. Breaking a written corporate policy is sometimes justification for termination of employment.

About the author: Serdar Yegulalp is editor of Windows Insight, a newsletter devoted to hints, tips, tricks, news and goodies for all flavors of Windows users.

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