If you are using an Exchange account or Office 365, all data in Outlook such as email messages, calendars, contacts etc. are saved in the form of an OST file. This feature allows you to access emails and other data in Outlook even without an internet connection.
The OST file gets bigger and bigger as and when you send or receive messages, add contacts or calendar information and so on. But it is important to understand that like all other file types, OST files also have a certain size limit. If this limit is exceeded, the file may get corrupt. Following are the symptoms of corruption in OST files.
Corrupt OST files may show symptoms such as
- Outlook application pauses
- Data cannot be added to the OST file
- Difficulty in syncing with the Exchange server when the internet is connected
Now let us see the methods you can use to reduce the size of your OST file.
Solution 1: Compact OST file
Before you compact the OST file, it is a good idea to clear unwanted items from Outlook and also empty deleted items folder. To do so, follow the steps below.
Step 1: Go through your emails and other data in Outlook
Before you compact your OST file, go through your emails, calendars and all folders in Outlook and delete what you don’t need. Although this directly doesn’t reduce the size of your data file, it can still help to clear out items from your Outlook.
Step 2: Empty deleted items folder
It is also a good idea to empty the deleted items folder before you compact the OST file. So go ahead with the steps below to empty deleted items folder.
- Click on File in Outlook and select Tools
- Select Mailbox cleanup from the drop-down menu under Tools
- In the dialogue box that opens, click on Empty
- You will be asked to confirm if you want to delete the items permanently from Deleted Items folder
- Click on Yes to proceed
Now your deleted items folder will be deleted and you will have some space freed up in Outlook.
Step 3: Compact the size of the OST file
Once you have cleared unwanted items from Outlook and emptied Deleted Items folder, you are ready to compact the OST file.
- Open Outlook and click on File in the menu bar
- Select Account Settings > Account Settings
- In the Data files tab, select the .ost file you wish to compact and click on Compact Now
- Then click Ok
Solution 2: Archive items from the OST file
Of course, another option is to archive items from the OST file so its file size is reduced. To archive the file,
- Open Outlook and click on File in the menu bar
- Select Cleanup Tools and in the drop-down menu, select Archive
- In the archive window that opens, select a folder to archive and also select ‘to archive items in that folder that are older than a specific date’.
Once you have made these choices, click Ok to begin the archive process. After the process completes, you will have an OST file of relatively less size.
Conclusion
These steps described above can be used to reduce the size of the OST file and prevent corruption. However, if your file is already corrupt, you can use a tool called Remo OST to PST converter to convert the corrupted OST to a healthy PST, using which all contents like emails, contact, calendars etc. can be recovered.
Once the file is repaired and items recovered, you can archive or compact the file regularly as a precaution to prevent corruption issues in future.