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An OST file is an offline copy of all your Outlook mailbox data. This helps users to work offline when the Exchange server connection is not available. However, if you make any changes to your OST file, then it will reflect once the connection is established. Due to the vast quantity of information stored in the OST file, the size of the OST file gets large. Having a large-sized OST file affects performance and user experiences, frequently freezing Outlook, and sometimes results in the error Outlook OST file too large.
Why is Outlook OST file so large?
The OST file includes emails, attachments, calendars, contacts, notes, tasks, schedules, etc. All these items have been piled up since the activation of the account. So it is necessary to keep a check on the OST file size to prevent the OST file from being inaccessible.
There can be various other reasons for the Outlook OST file too large, some of them are:
- Large Number of Emails: If your Outlook Inbox & Sent Items folder have too many emails, then your OST file will be large in size. As mailbox data increases, the OST file also expands accordingly.
- Oversized Attachments: Emails contain attachments in the form of files, photos, videos, and many more. These large files contribute significantly to the size of the OST file.
- Complete Archive: If you set your Outlook to cache all your mailbox data, including history, then your OST file will be large in size.
- Deleted Item Not Cleared: Outlook saves all the email folders, including Deleted Items. If your deleted item folder is not cleared, then that data will also be stored in the .ost file.
- Multiple Shared Mailboxes: If you have connected multiple accounts to Outlook, then all the data will be saved in the .ost file. In that case, it will increase the size of the OST file.
Symptoms When Your OST File Is Too Large
There can be various risks involved when the Outlook OST file too large. Some of them are –
- It will slow down the Outlook performance, such as a delay in loading or sending emails.
- A large OST file can slow down the indexing process, which will affect the search feature.
- Too large OST file can cause you an issue. Sometimes you cannot open the Outlook data file on your system, which hinders your working process.
- Too big .ost file is vulnerable to corruption and can lead to data loss.
- If the user wants to convert OST to PST, then tolling a large data file can cause the issue.
Fix “Outlook OST File Too Large” Error (Quick Methods)
The various methods listed below are effective in quickly resolving Outlook OST file too large issue and restoring smooth Outlook functioning.
1. Delete Unnecessary Emails: The large file present in your mailbox is one of the reasons for Outlook OST file tool large issue. Find the large file, and if it is not important, then delete it. For that –
- Go to Search Folder > Large Mail.
- Review the emails and delete large messages.
2. Remove Large Attachments: The large attachments present in your Outlook take too much space. Save attachments to your computer and then delete them from Outlook.
3. Empty Deleted Items and Junk Email: When you delete emails from your inbox, they are not permanently deleted; these emails are still present in the Deleted Items folder. Users have to empty the Deleted Items folder to permanently delete these emails to free up some space.
4. Archive Old Emails to New PST: To reduce the size of a large Outlook OST file, you can move older emails that are no longer required to a new PST file. After that, you can delete them and make space for the new one.
- Open Outlook, Click on File > Tools > Clean Up Old Items.
- Now select folders and a date range to move emails to a new PST file.
- Save as a PST file.
5. Reduce Offline Mail Storage: You can limit how much mail Outlook stores offline. Set the limit and maintain the OST file size. Steps to set a limit –
- File > Account Settings > Change.
- Adjust the Mail to keep the offline slider.
6. Disable Sync for Unnecessary Mailboxes: There can be various unused mailboxes present in your mailbox. Remove shared mailboxes you don’t use frequently.
7. Compact the OST File: After deleting data, compact the OST file to reclaim space. Steps include:
- File > Account Settings > Data Files.
- Select OST > Settings > Advanced > Outlook Data File Settings > Compact Now.
If all these solutions don’t work for you, then you can try the BLR OST to PST Converter Tool. The software will handle your large OST file without affecting your data. With it, you can effortlessly convert OST to PDF, PST, EML, CSV, etc. In this way, you can shrink the size of a large OST file. Try out the demo version of OST Converter software for further details.
How to Prevent OST File from Getting Too Large
- Delete emails that are no longer required to free up space.
- Save email attachments outside Outlook.
- Regularly run the Compact Now feature to compact the OST file.
- Don’t keep all emails in cache; keep only recent emails by managing the cache setting.
- Don’t sync all mailboxes; share only the mailbox you regularly use.
Conclusion
The Outlook OST file size depends on several factors, such as emails with attachments and multiple copies of the same email in different folders. As the OST file continues to grow over time, it impacts the performance of Outlook, directly resulting in Outlook freezing more frequently. Thus, regular maintenance of the Outlook OST file is required to keep Outlook free from any errors and to ensure smooth operations.
