Microsoft Outlook 2010: Although mostly identical to Outlook 2007's files, a few things have changed, including the default location for a POP3 pst file is in the My Documents folder and the nickname cache (NK2) is not used by Outlook 2010. See Microsoft Outlook 2010 Backup and Dual Boot File Locations for specifics.

We often get questions like "Where is my Outlook data stored?" "Where are my contact?" "How do I backup my calendar?"

Everything, your mail, calendar, and contacts in your Outlook folders are either in a mailbox on an Exchange Server (if you use an Exchange server account) or in Personal Folders .pst files on your computer.

Backup and dual-booting between Windows versions all involve using the same files. There is no backup process built into Outlook. To back up, simply exit Outlook, then copy the files you want to back up. Below we provide a chart of Outlook 2007 file locations, followed by notes on particular files.

Microsoft offers a Personal Folders a backup tool which you can use, but since it can cause Outlook to not close properly or quickly and only supports copying the PST, we recommend copying the files yourself or using a batch file or script to make copies before opening Outlook.

These files are also the ones that you'd want to copy back and forth between machines if you need to use the same information at the office and at home, for example. If you have Outlook profiles, name them the same on both machines, so you can use the same files easily. Then use Tools | Account Settings to use the files that you copied.

See Moving Outlook to a New Computer for the steps needed to move Outlook files to a new computer.

See How to move the IMAP personal folder (*.pst) for the proper way to move IMAP and Internet Subscription folders.

If you dual-boot, your profile can point to the same .pst and .ost files, but you would need to copy other files to the correct location on the second operating system.

Video Tutorial: How to create a new profile

Windows XP File Locations | Vista & Win7 File Locations | Personal Folders Files
Offline Folders File | Personal Address Book | Other Files | Accounts
Tools | Notes | More Information

Windows XP File Locations

Where do you find these files? You can always start by using your operating system's Search or Find command to locate the particular file types. You may need to use Tools | Folder Options | View in Windows Explorer and select Show hidden files and folders.

When using Windows 2000/XP, Outlook stores *ost, *.oab, and extend.dat in C:\Documents and Settings\\Local Settings\Application Data\Microsoft\Outlook. Extend.dat and MSN Connector message stores cannot be moved. See How to move the IMAP personal folder (*.pst) for the proper way to move IMAP and Internet Subscription folders.

All other Outlook configuration files are stored in C:\Documents and Settings\\Application Data\Microsoft\Outlook and cannot be moved.

Tip: Copy and paste these lines in Windows Explorer address bar to open the folder:

To access the folder holding the toolbar, VBA, rules, and nickname files, copy and paste:

%USERPROFILE%\Application Data\Microsoft\Outlook

To see the message store files, copy and paste:

%USERPROFILE%\Local Settings\Application Data\Microsoft\Outlook

Note: Storing Personal Folders on an network file share is not recommended and may cause corruption and data loss.

Vista and Windows 7 File Locations

Where do you find these files? You can always start by using your operating system's Search or Find command to locate the particular file types. On Vista you may need to browse to Windows Explorer's Organize | Folder and Search Options | View tab and select Show hidden files and folders.

Vista replaces Documents and Settings folder path with a Users path. As a result, in Vista you'll find Outlook stores the PST and OST, in C:\Users\\AppData\Local\Microsoft\Outlook.

Live Connector message stores can not be moved but POP3 and Exchange offline or cache storage can be moved to other locations. See How to move the IMAP personal folder (*.pst) for the proper way to move IMAP and Internet Subscription folders.

All other Outlook configuration files are stored in C:\Users\\AppData\Roaming\Microsoft\Outlook and cannot be moved.

Tip: Copy the following lines and paste into Vista's Start menu "Start Search" field to open these folders:

To access the folder holding the toolbar, VBA, send & receive settings, and nickname files, copy and paste:

%USERPROFILE%\AppData\Roaming\Microsoft\Outlook

To see the message store files, copy and paste:

%USERPROFILE%\AppData\Local\Microsoft\Outlook

Note: Storing Personal Folders on an network file share is not recommended and may cause corruption and data loss.

Personal Folders Files

If you are not connecting to Microsoft Exchange Server, all your Microsoft Outlook data is stored in one or more Personal Folders (.pst) files.

Check the properties for Personal Folders in Tools | Account Settings to determine the exact location on your system.

Some people like to export a folder, such as Contacts, to a separate backup .pst file. That's fine for the data, but it does not back up any folder customizations such as views and custom forms. If you want to back up those, too, copy the entire folder to a new .pst file instead of using the export feature.

Also see:

• Why .pst Files Are Unsupported Over a LAN or WAN Link
• XCLN Default Personal Folder File Creation Path Needs to Be Configurable - hotfix available; provides ForcePSTPath registry value

Offline Folders File

If you use Microsoft Exchange Server, you may have an offline or cache mode folders (.ost) file. You shouldn't need to back it up, since you can always refresh it by synchronizing with the server. However, be sure you understand the procedure for Convert an Exchange Offline file (OST) to a Personal Folders file (PST) . If something ever goes wrong with your Exchange Server mailbox, this technique can save time and information, but you must apply it before you try to connect to the server again.

Personal Address Book

Most Outlook users no longer have a PAB because the Personal Address Book (.pab file) is deprecated. If you still have a PAB, the contents need to be imported into your Contacts folder. The *.pab will not open in an Outlook 2007 profile.

To Import the *.pab, go to File | Import and Export. Choose Import from another program or file, then scroll down and choose Personal Address Book.

Other Files

Outlprnt file contains your custom print settings.

Some other miscellaneous files, not necessarily worth backing up:

• Extend.dat -- Information about installed add-ins. Will be recreated if you delete it.
• Outitems.log -- Outlook items to be placed automatically in the Journal
• Offitems.log -- Office items to be placed automatically in the Journal
• Frmcache.dat -- Outlook forms cache file. See How the Microsoft Outlook forms cache works.

Accounts

Account information is held in the user's Windows registry, not in a file, at HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows Messaging Subsystem\Profiles

While you could export this key, its not generally recommended because it contains absolute paths to files (in your user account folders) and information about installed add-ins. If the path is not exact when you restore it the profile will be corrupt.

Notes

If your network is set up so that you can use Outlook at any machine ("roving profiles"), your Outlook files may be in a different location. Try using Start | Find to locate each type of file. If you don't see any .pst files after you search, you may need to adjust the settings in Windows Explorer to show hidden and system files. Choose Tools | Folder Options, then switch to the View tab, and select Show hidden files and folders.

Personal Folders .pst files are among the files that are normally not included in a Windows 2000 (or later) offline files synchronization. However, you can edit the system policy that controls the file types so that .pst files can be included. See Error Message Files of This Type Cannot Be Made Available Offline.