This article explains how to keep the PST file small by archiving your old mail. Instructions in this article apply to Outlook for Microsoft 365, Outlook 2019, Outlook 2016, Outlook 2013, and Outlook 2010.

What to Know

  • In Outlook, select File > Info > Account Settings > Account Settings.Go to the Data File tab and select Add. In the New Outlook Data File dialog box, choose Outlook Data File and then select OK.Name the archive, choose a location for it, and select OK. Drag and drop entire folders into the new Archive folder.

How to Archive Old Mail in Outlook to Keep the PST File Small

As the pile of mail you keep in Outlook grows, so, typically, does the time it takes Outlook to do what you want it to do. The PST file size limit looms. (The PST or “Personal Folders” file is where Outlook keeps all your data, including calendars, contacts, and emails.)

To create an archive of old messages in Outlook separate from the PST file you use every day:

  • Select File and choose Info.
  • Select Account Settings and choose Account Settings from the menu. The Account Settings window will open.
  • Select the Data File tab.
  • Select Add. The New Outlook Data File dialog box will open.
  • Select Outlook Data File and choose OK.
  • Enter the name for the archive under File name and select the location where you want to save the file.
  • Select OK and close the window.

Move Mail to the Archive

To populate your newly created archive PST, drag and drop entire folders to the root folder newly appearing under Mail Folders. This is handy if you already have an Archive folder that contains, say, all of last year’s mail. Just drop it into the archive PST.

Select File and choose Info.

Select Account Settings and choose Account Settings from the menu. The Account Settings window will open.

Select the Data File tab.

Select Add. The New Outlook Data File dialog box will open.

Select Outlook Data File and choose OK.

Enter the name for the archive under File name and select the location where you want to save the file.

Select OK and close the window.

Alternatively, to archive individual items:

  • Right-click the root folder named after your archive PST under Mail Folders.
  • Select New Folder from the menu.
  • Type the desired folder name.
  • Make sure Mail and Post Items is selected under Folder contains if you want to archive emails. For archiving other items, choose the appropriate category.
  • Drag and drop individual or groups of emails onto the newly created folder.
  • To move all mail preceding a certain date in a folder (or nested folders), select File > Info.
  • Select Tools and choose Mailbox Cleanup.
  • Select AutoArchive from the menu that has appeared.

Close the Archive PST File

After you have archived all items, you can close the PST file in Outlook:

Right-click the root folder named after your archive PST under Mail Folders.

Select New Folder from the menu.

Type the desired folder name.

Make sure Mail and Post Items is selected under Folder contains if you want to archive emails. For archiving other items, choose the appropriate category.

Drag and drop individual or groups of emails onto the newly created folder.

To move all mail preceding a certain date in a folder (or nested folders), select File > Info.

Select Tools and choose Mailbox Cleanup.

Select AutoArchive from the menu that has appeared.

  • Right-click the root folder of your archive PST under Mail Folders.
  • Select Close “___” from the menu.

Access Mail From a Closed Archive PST File

To retrieve messages from an archive PST file you have closed:

Right-click the root folder of your archive PST under Mail Folders.

Select Close “___” from the menu.

  • Select the File tab and choose Open & Export.
  • Choose Open Outlook Data File.
  • The PST file and its folders will appear under Mail Folders, ready for action.

A Small PST File Is a Fast PST File

It pays to keep the size of your main PST file small and manageable. You can have Outlook do some of that using AutoArchive or divide your messages between more PST files, which can be painless and swift.

Select the File tab and choose Open & Export.

Choose Open Outlook Data File.

The PST file and its folders will appear under Mail Folders, ready for action.

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