How to reduce and reduce mailbox size in Microsoft Outlook


Clients for Microsoft Outlook, Outlook or a live email service store emails and attachments offline. As you receive and send emails, the size of your database keeps growing. It means your mailbox size keeps growing while you check to see if you can access your email when you don’t have an internet connection. In this post, we will share how you can reduce and reduce your mailbox size in Microsoft Outlook.

Small and shrink mailbox sizes in Microsoft Outlook

The downside to getting your mailbox bigger is that it slows down the experience. It takes a long time to open or search for anything. On top of that, email providers like Office 365 limit the maximum size of your mailbox. You won’t be able to send or receive emails unless you reduce your mailbox size in Microsoft Outlook.

Where all the data in your Outlook mailbox is stored

When you use the POP or IMAP feature, all files, emails, folders, contacts, etc. are stored in an Outlook data file (.pst). If you’re using an Office 365, Exchange, or account, you can use your mailbox data in an offline Outlook data file (.ost). Deleting emails and attachments can help, but storing all the information in a PST file doesn’t shrink itself.

Note: There are two ways to delete files in Outlook. Using these files and manually reducing the file size of your mailbox will help even more.

Bad or Missing Configuration

Compress and shrink Outlook data files (.pst)

The advantage of a PST file is that it automatically compresses the database in the background when you delete emails. The compacting process occurs when you are not using Outlook. You can also do the following steps manually to compress it.

  1. Open Outlook and delete the items you don’t need. When removed, the file will be saved in the “Deleted Items” folder. Right-click and empty.
  2. Click File> Account Settings> Account Settings.
  3. Switch to the Data Files tab. Select the data file you want to compress. Then click Settings.
  4. Click the Advanced tab> Outlook Data File Settings.
  5. In the Outlook Data File Settings dialog box, click Compress Now, then click OK.

It may take a few minutes to compress depending on the PST file size.

Compress and shrink offline Outlook data files (.ost)

Many email accounts use offline Outlook data files to store their data. OST or offline Outlook data files are similar to PST or Outlook data files with one exception. You cannot import or export from offline Outlook data files (.ost).

  1. Click File> Account Settings, Account Settings.
  2. On the Data Files tab, click the data file you want to compress, then click Settings.
  3. Click the Advanced tab> Outlook Data File Settings.
  4. In the Outlook Data File Settings dialog box, click Compress Now, then click OK.

Use the mail cleanup tool

Outlook provides a built-in mail cleanup tool or Outlook Attachment Cleanup tool can retrieve old and large messages that can be deleted or moved to a PST file. You can also get rid of email copies that conflict with your email server. Sometimes the server deletes the file, but the file is also available in the space occupied by the client.

Run the mailbox cleanup tool

  1. Click File> Tools> Mailbox Cleanup.
  2. To do what you want, choose View Mailbox Size, Find Previous, Find Larger Items, View Deleted Items Size, Empty Deleted Items Folder, View Conflicts Size or Empty Conflicts.

Use the cleanup dialog tool

Office 365 Outlook 2019 Outlook 2016 Office 2013 and other conversation organizer tools for business Outlook . The same goes for a conversation or email conversation list. The “conversation tool” is smart. It will evaluate the content of each message, and if a portion of the e-mail is available in the preview message, it will delete it.

You have three more options to reduce and reduce your mailbox size in Microsoft Outlook.

  • Organizes confirmation of the selected conversation.
  • Folder Cleanup reviews the selected folder.
  • Folder and subfolder cleanup also checks subfolders.

Here are the most helpful tips to reduce and reduce your mailbox size in Microsoft Outlook. But always make sure you don’t accidentally delete important files.