What Is NST File in Outlook and How to Use It?

Do you want to know what is NST file in Outlook? Don’t be much concerned about thinking this question. As in this article, you will get complete information about *.nst file extension and how to make it usable for different purposes.

If you use Microsoft Outlook, you are probably familiar with the terms OST (Offline Storage Table) and PST (Personal Storage Table). But some of Outlook users don’t know what kind of file is NST.

What Is an NST File Extension?

When a user configures their Microsoft Office 365 account with Outlook, an NST file is created automatically. After successfully configuring an Office 365 account, Outlook begins synchronizing messages and creates a cached local copy of them called GST (Group Storage Table). Thereafter, Microsoft 365 users can access group emails and other data offline mode similar to OST files. GST or OST files are saved in the same folder on the local computer.

Outlook's slider controls or manages the amount of data synchronized in GST (.nst extension). An NST file, also known as an Office 365 group NST file, is used to store only calendars and group conversation messages in Office 365 groups. It may also store contacts in such cases, as some conversations may contain contacts.

What Is the NST File (Generated with Outlook Connector)

Additionally, the Microsoft Outlook Connector for IBM Notes Add-in generates an NST file that can be used to connect to HCL / IBM / Lotus Notes via Microsoft Outlook. NST files generated by Outlook Connector can be used to store Lotus Notes email messages and other critical data on a local computer. The NST file format is similar to the OST file format.

How NST Extension Get Created?

Follow the given steps for generating Outlook Data File NST.

  1. Open Microsoft Outlook Add Account Wizard on your computer. Enter Microsoft 365 email address in specific field and click on Connect button.
  2. Outlook preparing for adding new account in its database. You can see the displaying message as “We’re Getting Things Ready”.
  3. Now it is asking for Office 365 email password, enter it and click on Ok button.
  4. Thereafter, you will see a dialog box about Mail Delivery Location, press Ok.
  5. After that, you can see the message i.e., Account setup is complete and click on Ok to confirm.
  6. MS Outlook has begun receiving email messages from the Office 365 account configured. This process will take some time, depending on the amount of data stored in your Microsoft 365 account.
  7. After downloading Office 365 emails, you can see synchronized data in MS Outlook. Now NST file get created successfully.

How to Find NST File Location?

The default storage location of NST file is same as OST file. You can follow the given steps for Outlook NST file location.

  1. Run MS Outlook email client and right click on configured Office 365 account and choose Data File Properties option.
  2. After that, hit on the Advanced option from current opened wizard.
  3. Then, new pop-up window will be opened, click on Advanced tab << Outlook Data Settings.
  4. Copy displayed location and click on Ok to close current dialog box. Now Exit MS Outlook and press Windows + R to open Run Wizard.
  5. Enter copied location path, enter on Run dialog box and press Ok button.
  6. Thereafter, default storage location of NST file will be opened.

Go to following location to get NST files

Windows XP - C:\Documents and Settings\%username%\Local Settings\Application Data\Microsoft\Outlook\

Windows Vista, 7, 8, 10, and 11 - C:\Users\%username%\AppData\Local\Microsoft\Outlook\

What Kind of File is NST?

Here is the technical specification of NST file.

Developer – Microsoft

File Type – Email Files

Category – Data File

Format – Binary

Compatible Platform – Windows & macOS

How to Make NST File Usable?

Option 1Download Free NST File Viewer Tool that is capable to view GST (Group Storage Table) file data in the absence of Microsoft Outlook. This application permits to read complete data of NST files i.e., Emails, Contacts, Calendars, etc.

Option 2Download NST to PST Converter that allows to change Outlook data file .nst into 30+ formats. Therefore, this is one of the best ways to use NST files with multiple email clients, email services, and standard file extensions.


Now you have complete knowledge about what is NST file in Outlook 2021, 2019, 2016, 2013, 2010, 2007, etc. and its storage location. We have also suggested you dual options to make NST files usable. Hope this information will be helpful to you to know about what is an NST file extension.

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