How to Compress PST or OST File in Outlook 2016, 2013, 2010 & 2007

Microsoft Outlook is a very vast field to work. As a frequent user of Outlook, we are very well aware with its data files. “PST and OST file” being the database files of Outlook, store emails, calendar, contacts, tasks, values etc. Now, it is likely that the more we work with Outlook, the larger PST or OST file we get. This large size of PST or OST file can cause troubles like slowing Outlook, degrading Outlook performance, corruption in PST file etc. If we avoid to compress PST file in Outlook, we won’t be able to get rid of such problems, so, we indeed compact PST file in Outlook 2016, 2013, 2010 and 2007. Now, I am going to explain how to compress PST or OST file of Microsoft Outlook manually step by step.

Manual Method to Compress PST or OST File in Outlook 2016, 2013, 2010, 2007, 2003

If the problem to reduce a PST file doesn’t let you work properly on your Outlook, we are providing various methods to overcome such issue. Just apply any of the methods mentioned here and compress Outlook PST files easily. Let’s see how to Compact PST file Manually Step by Step:

For Microsoft Outlook 2016, 2013 & 2010 :

Case 1. If Outlook 2016 and 2013 is configured with IMAP account, then OST file is generated in the default location. So, the steps below I am going to elaborate are for OST file compression.

    1. Open Microsoft Outlook.
    2. Go to the File tab.

3. Go to Info. Click Accounts Settings & again click Accounts Settings.

4. Hit on Data Files tab >> Settings >> hit Compact Now.

5. Press OK, and then Close.

Case 2. Just like this, if Outlook 2016 and 2013 is configured with POP, then PST file is generated. Now, in the below steps, I am going to explain are for PST file compression.

    1. Open Microsoft Outlook >> Click on file tab.
    2. Go to Info >> Account Settings, press Account Settings again.
    3. Go to Data files tab, click on Settings.
    4. A new window will pop-up. Click on Compact Now button to compress PST file.

Case 3. If we use MS Exchange in Outlook, OST file will generate & we will have to compress OST file.

For Microsoft Office Outlook 2007 with Exchange Account

    1. Open MS Outlook.
    2. Go to the Tools menu >> Account Settings.
    3. Choose Microsoft Exchange Server in the list, & hit on Change
    4. Select More Settings.
    5. Go to Advanced tab & pick Offline Folder File Settings.
    6. Select Compact Now.

So, these are the steps used to compress OST file.

For MS Office Outlook 2003 and previous versions of Outlook

1. Go to Tools menu & select E-mail Accounts.

2. Choose View or change existing e-mail account & hit Next.

3. Select Microsoft Exchange Server >> Change.

4. Hit on More Settings.

5. Now, visit Advanced tab & select Offline Folder File Settings.

6. Hit Compact Now.

7. After the compact process, Press OK two times.

8. Press Next, and then click on Finish.

How to Compress PST File in Microsoft Outlook 2007

    1. Open MS Outlook.
    2. Click on File tab >> Data Management

3. Now, click on Data Files and choose your Personal folder.

  1. 4. Select Settings >> Compact Now

5. Press OK & then Close.

Limitations of Manual Methods to Compress PST or OST File in Outlook

All the above mentioned methods for PST and OST compression are very simple and easy to implement, but along with that, these methods also contain some drawbacks which are listed below:

i) Time consuming: Manual methods to compress PST or OST file, are time consuming and can take hours to process.

ii) Complexity: For some users, manual methods can be quite complicated and user might get difficulty to understand and interpret the whole procedure.

iii) Can’t Reduce Over-large data file: Although manual methods are reliable, but these methods are unable to shrink very large sized PST/OST files in Outlook.

Bottom Lines

In the above article, as we discussed manual methods to compact PST files in Outlook 2016, 2013, 2010 & 2007 and also with MS Exchange Account, we came to a conclusion that these methods are indeed very useful, but if we have a very large size of PST or OST file, say 20 GB sized data file, then how are we going to reduce it? In such case, we can use SysTools PST Compress Tool to decrease the size of Outlook data file, as it overcomes all the limitations of manual methods and works effectively.

Ashish Ratan Singh

Being a technical blogger, Mr. Ashish Ratan Singh has a sufficient knowledge of different technologies such as Exchange Server, Office 365, SharePoint, but his core expertise lies on Microsoft Outlook. He has been working in an IT industry for more than 3 years and with all these years, he has now become an expert in data recovery and cloud backup. Moreover, he has a keen interest in solving the technical problems and to address the pain points of organizations to make them more productive.

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