Know How to Resolve OST File Too Large Error in Outlook

As a user creates his mailbox data & then receives email items on a frequent basis, the MS Outlook mailbox goes on to grow a great deal. The files in question here are the offline Outlook Data files or the OST files, which keep augmenting in volume as large amounts of data keeps adding to the user’s mailbox. If the files are in UNICODE format, this size limit can even go up to as large as 50 GB. So, it appears like OST file is too large. However, ANSI format files could possibly grow up to the size of 2 GB. Also, if somehow some data gets deleted, then the size won’t reduce that much as per the volume of deleted items. This mostly happens due to the free space being acquired by white spaces thereafter. But, there could be some ways, which may help in better management of large file by the process of divide oversized OST file by size.

Technical Overview of OST File

OST file is Exchange mailbox’ replica, which gets locally stored on end-client machines during Cached-Exchange-Mode. OST files are automatically created through Outlook’s offline-folder-feature. OST files tend to get active while Exchange’s offline mode is on and it is known as Offline Storage Table and while the replicas get increased, OST file too large error occurs. When network connectivity is again retained, these OST files are automatically synced to the server’s account and entire data updates right after. The alterations, changes as well as any modifications that are being made to these OST files during offline work mode gets updated automatically to Exchange Server when the network connection is established. During this synching process, any of the deleted items or email items that are permanently deleted gets eliminated from MS Exchange’s mailbox-folders.

Why OST File Too Large Error is Shown

OST files hold entire mailbox data generated while the account was created and keeps on receiving more and more data since then unless any items are deleted. Therefore the error i.e file Outlook .ost is too large file for the destination file system is described below with quick methods.

Components Contained in Large .ost File

• All types of mailbox items like emails, contact addresses, notes, calendars, tasks, journals, etc
• Hidden items
• Public-Folder-Favorites
• Also, shared folders from any additional mailbox or mailboxes that associated with this Exchange’s account

OST File Too Large Error Situation Reduces By Mailbox Management

The huge file could affect the client’s machine and also it is unfavorable for the Exchange Server too. So, all-in-all it’s imperative to reduce the size of OST files and manage mailboxes on a regular basis for ensuring proper functionalities of the mailboxes. When the size, as well as volume of any OST files, is slashed, then it is sure to make the mailbox performance better in case a good amount of email data is deleted from the mailbox by the users.

Deleting Unwanted Mailbox Items to Avoid Large .ost File Error

• First, open Folder-List view
• Then, click Folder List’s icon at bottom of Navigation-pane
  • Or Press Ctrl+6 keys
• Now, click File tab
• Click Account Settings
• After that, select Account Settings
• Under Data-Files tab, select file needed for compaction
• Click Settings
• Lastly, click Compact Now

Better Alternative is by Auto Archiving of Very Large OST File

• First, click File tab
• Then, click Cleanup Tools
• Select Mailbox-Cleanup now
• After that
  • Either one can move older email items located in mailbox to some archive folder
  • For this, click the option of AutoArchive
• Or email items existing in Deleted-Items folder can be emptied
  • For this, click Empty

Commercial Intervention for OST File is Too Large

The problem of .ost files growing too large in size is a common issue faced often by users all around. Manual methods can be used but again they always come with their fair share of risks, data loss threats and lengthy procedures to resolve very large ost file issue. SysTools OST Splitter is a proficient tool for transferring data while keeping all of the attributes fully intact. This tool works well with various Outlook versions, both Unicode as well as ANSI versions. Additionally, admins can easily perform OST splitting operation using this tool which reduces the error of large .ost files.

Conclusion

OST file too large error situation can be avoided by above given manual methods. The process may seem to be useful enough but are also quite lengthy and time-consuming. If they are not properly executed, it may lead to the deletion of some email items present inside the mailbox. For preventing such grave data, one can choose to use some commercial tool for converting OST to PST format and then storing the copy locally on the end-client system and thus the error OST file too large will be eliminated.