About PST Formats, Use, and File Size Limit

All versions of Microsoft Outlook use PST (Personal Folder) file to hold e-mails, contacts, calendar entries, and other data. Though all these versions seem to use same kind of PSTs, but as the fact Outlook uses two different formats in PST: ANSI (American National Standards Institute) and Unicode (the standard format that is able to present almost all type of characters). These two type of PSTs are distinct with respect to their file size limitation, but the issues that can occur due to large file size and compel you to Split PST File are almost similar.

Here is the typical use, file size limitation, and flexibility in file size of both type of PSTs. The article further mentions some problems that can occur due to large size of Outlook PST and ways to resolve them.

ANSI PST

Use: Microsoft Outlook 97-2002, IMAP4 (Internet Message Access Protocol Version 4rev1) and HTTP (Hypertext Transfer Protocol) accounts of Outlook 2003, explicit use in Outlook 2007

File size limitation: 2 GB

Flexibility in file size: Hard-core limit, cannot be configured

Unicode PST

Use: Outlook 2003 except in IMAP4 and HTTP accounts, Outlook 2007

File size limitation: Default value- 20 GB,

Flexibility in file size: can be configured using registry editing

Large PST size issues

A PST with considerable size is never recommended. Such files are prone to several issues such as mentioned below:

(1) File corruption vulnerability (especially an ANSI PST).

(2) Performance issues.

(3) Data management problems.

(4) Require significant time while typical operations like importing or restoring.

Since you keep on receiving data in Outlook, the PST file grows to its maximum or defined file size value. Thus you should always keep a check on the file size to ensure proper action.

Ways to reduce PST size

The following measures can prove beneficial to reduce the overall size of PST:

(1) Delete the unnecessary e-mails timely.

(2) Compact the PST.

(3) Archive old e-mails (recommended- use Auto-archive feature).

(4) Split PST.

You can Split PST File using third-party applications that are designed exclusively to divide a large PST file in several smaller files in a single attempt.

Stellar Phoenix PST File Splitter is a professional utility that splits large sized PST file on the basis of e-mail ID and date. The Split PST utility supports MS Outlook 2007, 2003, 2002, and 2000. The tool has an interactive display that makes the utility easily operable.