File Converters

All About PST File

To make the right decisions when it comes to the use of PST files, you must understand the essence of PST files, their specs, and some potential limitations. It is worth figuring out how to manipulate datafile locations and work with Outlook data files according to the specific requirements.

Exchange administrators are concerned about PST files. Many believe that a PST file isn’t the best choice when it comes to the primary storage for Outlook data for a variety of reasons:

Accessing a PST file over a network isn’t supported and can create a real problem for those who need to modify an Outlook data file;
PST files need to be stored locally on workstations of a user, which complicates archiving and recovery processes;
PST files take up a way more space on your hard drive compared to the corresponding data on the Exchange server;
PST files don’t support Single Instance Storage (SIS) storage, which makes them extremely vulnerable;
The data stored in the PST file is impossible to access from any external source, such as a workstation or Outlook Web Access (OWA) client;
PST files aren’t well protected. For example, passwords are easy to hack or even remove them using special tools.

Therefore, it is best to have a local back-up of a personal storage table PST. If the user needs a local copy of the Outlook data, cached Exchange mode is preferred. This mode creates an auxiliary copy of the Outlook data file with the .ost extension. Thus, a user can work with the local instance of Microsoft Outlook in the event of a disconnection between the workstation and the Exchange server. However, there are some situations where PST files are useful. Many companies use Microsoft Outlook to access message processing tools other than Exchange, and most of them use the Internet Protocol POP3 or IMAP4. The latter synchronizes with the server mailbox, while the former can be optimally configured to store copies of Outlook data files on the Exchange server. Personal storage table PST files are useful for organizing low-cost archives.

Quick answer: A PST (Personal Storage Table) is the Outlook data file that stores your mail, contacts, calendar, tasks, and notes in one local file. It is best used as a low-cost archive or backup, holds up to 33 TB but performs best under 10-12 GB, and can be opened or converted to PDF, DOC, and other formats with Total Outlook Converter.

Creation of PST File

To accomplish the above tasks, you need to use special file utilities, such as EML to PST tools. For example, a PST to PDF converter allows you to merge email messages saved in .pst format into one doc file. To create a PST file, select the appropriate option on the first page of the wizard:

Create a new PST file;
Specify the path to the root folder of the mail database;
Wait for the PST import to finish.

Keep in mind that unlike similar PST utility tools, the converter is unique due to its fast message processing algorithm, which allows it to carry out the necessary conversions very quickly.

How I Can Open PST

Do you have a PST file? You have a couple of options here. Microsoft Outlook is the standard email client and information manager used by millions of people on their Windows 10 machines. This software is a great choice to use for opening PST files in Windows 10. There is no need to install any other third-party software if you have Microsoft Office Outlook up and running.

However, if you want to open a PST file on your Windows 10 PC or any other machine running on Windows but don’t have Microsoft Office Outlook installed, there is an alternative approach for you to follow? Want to open a PST file without Outlook software? Here are the 5 ways to open without Outlook by using specialized software.

How to Import PST File

In most of these cases, PST data files that cannot be opened by Outlook remain on the user’s machines. To work with them, third-party services or services are required. Use the specialized application to import the PST files you need. Perform the below to speed up the process:

Find the exact location of Outlook data files that you need to import;
Open PST file in Microsoft Outlook menu by following the logic: File > Open & Export > Open Outlook Data File;
Remove old files from Outlook settings by following the logic: Menu > File | Account setting;
Open the Data files tab;
Remove the PST file from the list of data files.

How Big Can a PST File Be?

The allowed max size for Unicode-based PST files is 33 TB; however, the default size shouldn’t exceed 20 GB. By modifying the registry, this threshold can be increased or decreased. Of course, the processing speed of large Microsoft Outlook data files isn’t the optimal one. Even 20 GB is too much to be processed in one go. Sometimes a user may want to prevent personal folders from reaching the top limit due to backup and restore resource requirements. This is necessary to maintain a high level of performance or even save disk space. The recommended size is about 10-12 GB.

Total Outlook Converter Customer Reviews 2026

Rate ItRated 4.7/5 based on customer reviews

"The section on PST size limits and why storing them locally causes problems for our Exchange environment was exactly the reference I needed for a policy document. Pointed our whole helpdesk team to this page instead of re-explaining PST file mechanics on every ticket."

5 Star Alistair Grieve Exchange Administrator, financial services firm

"We were drafting guidance on where PST files should and should not live on the network, and this article laid out the storage limitations and network access issues clearly. The mention of Total Outlook Converter for handling PST data gave our team a concrete next step."

5 Star Marguerite Lachance IT Compliance Analyst, insurance company

"Good rundown of what a PST file actually stores and why Exchange admins get nervous about them sitting on local workstations. I would have liked a quick summary table of size limits by Outlook version, but the explanation itself was accurate and easy to follow."

4 Star Corey Vandenberg Desktop Support Specialist, manufacturing company

PST Files — FAQ ▼

What is a PST file?

A PST (Personal Storage Table) is the data file Microsoft Outlook uses to store mail, contacts, calendar entries, tasks, and notes in a single local file. It is created automatically when you use Outlook without an Exchange server. You can open its contents or convert them with Total Outlook Converter.

What is the difference between PST and OST?

A PST file is your primary local Outlook store and is fully portable. An OST is an offline cache copy created in Cached Exchange Mode, letting you work locally while disconnected from the Exchange server. The OST resynchronises with the server mailbox once you reconnect.

How big can a PST file be?

Unicode PST files support up to 33 TB, but the default cap is 20 GB and can be changed in the registry. For good performance most administrators keep a PST around 10-12 GB, since very large files slow down search, backup, and recovery.

Can I open a PST file without Outlook?

Yes. While Outlook opens PST files natively, you do not need it installed. Tools such as Total Outlook Converter and Outlook Viewer read PST files directly so you can browse folders, preview messages, and export them even on a machine without Microsoft Office.

How do I convert a PST file to PDF or Excel?

Open the PST in Total Outlook Converter, select the folder or messages, click the target format button (PDF, DOC, XLS, HTML, and others), set the output folder, and click Start. You can merge all messages into one document or save one file per email.

Why do Exchange administrators dislike PST files?

PST files are not supported over a network, must be stored locally, take more space than the same data on Exchange, lack Single Instance Storage, and are weakly protected since passwords are easy to remove. For these reasons they are best used as low-cost local archives rather than primary storage.

Are PST files secure?

PST password protection is weak and can be removed with common tools, and the data is not accessible from external sources such as Outlook Web Access. For sensitive archives, keep a local backup and consider exporting the contents to a controlled format like non-searchable PDF for sharing.