Outlook Data Files (.pst) created by using Microsoft Outlook 2010 are saved on your computer in the Documents\Outlook Files folder.

If you are using Windows XP, these files are created in the My Documents\Outlook Files folder.

Files created in previous versions of Outlook are saved in a different location in a hidden folder.

Windows 7 and Windows Vista : drive:\Users\user\AppData\Local\Microsoft\Outlook

Windows XP : drive:\Documents and Settings\user\Local Settings\Application Data\Microsoft\Outlook

For enabling about Hidden Folders in Windows, follow below few steps:

• Go to Control Panel.
• If you are in Category View then switch to Classic View.
• Select Folder Options category.
• A window will be open, now goto View tab.
• In Hidden files and folders option check Show hidden files and folders.
• Click Apply and then click on OK.

In Outlook 2003, pst-file format has been changed to UNICODE from ANSI. UNICODE format allows users to work beyond 2GB limit of ANSI formatted PST files. UNICODE format allows international character support.

• PST files created in Outlook 2003 and in later versions are in UNICODE format.
• Previous Outlook versions from 2003 can not open UNICODE formatted PST files.
• Outlook 2003 and later versions can open both ANSI and UNICODe formatted PST files.

Maximum size of PST files in ANSI format is upto 2GB only. If the size of file further exceeds, it will be corrupted and user would not be able to open it in Outlook anymore. In that case, you need to use Outlook Recovery tool to remove corruption from PST file and to recover it.

The new Unicode formatted pst-files have a configured maximum size of 20GB in Outlook 2003 and Outlook 2007. In Outlook 2010 and Outlook 2013 this limit has been set to 50GB.

• In Outlook, click the File tab.
• Click Help
• Under "About Microsoft Outlook", look at the Version value.
• It should say "(32-bit)" or "(64-bit)" next to the version number.