1. Home » Blog » Outlook OST File Size Not Reducing After Archiving

Outlook OST Size Not Reducing After Archiving – Fixed Up


The increasing size of Microsoft Outlook is obvious due its extensive use in various organizations for emailing purpose. Even when a user erases or deletes these email items the size of OST files does not reduces largely. Even the archiving method does prove to be helpful. This ultimately, leads to an error i.e. Outlook OST size not reducing after archiving. Now, the question arises is there any trick to rectify this error? Can we handle this issue manually? The answer is yes. There are some strategies to overcome this error associated with Outlook OST file size. We will come to that later; first let us go consider this query to understand the situation in a clear way:

“I am accessing Microsoft Outlook from a very long time. Now, from some days I am getting an issue that OST file size is not reducing. I do not know what to do in this situation; therefore, I want to know a relevant trick for the rectification of this problem. Please suggest me its urgent.”

Methods to Resolve Outlook OST File Size Not Reducing After Archiving

We have come up with two manual procedures to avoid this error:

Method 1: Manage the Size of Outlook’s Mailbox

For this, users can take the help of Mailbox-Cleanup tool to view the size of the entire mailbox of Microsoft Outlook. Moreover, with this it is also possible to view the size of a particular folder. Users can archive the older emails to an archive Outlook-Data-File and after this; they can empty the folder of Deleted-Items. To manage the size of the mailbox of Outlook data file, users can follow these steps as mentioned:

  • Firstly, you need to click on File tab
  • After this, click on Tools and then on Mailbox Cleanup
  • Now, follow any of these mentioned steps:
  • To view the size of the entire mailbox and of individual folder, hit on View-Mailbox-Size

If you wish to find the older email items, do this:

  • Choose Find items older than “x, which is the required value, days”
  • Then, put in a number between 1 and 999
  • Finally, click on Find
  • Choose Find items bigger than x KB
  • Then, type in a number between 1 and 9999
  • Finally, click on Find

  • For moving older email items in the mailbox to an archive Outlook-Data-File
  • Click on AutoArchive

Important Note: In case this solution does not prove to be helpful then, you can move to the alternative solution mentioned below to fix this problem.

Method 2: Compact the Size of OST Data File

Offline Storage Table file belong to Microsoft Exchange Server account. In addition, these files are not deleted where Exchange Server runs in the process of deletion. Therefore, shrinking these files is another option to enhance the performance of Outlook. Now, to compact OST files you can follow these steps one after the other:

  • First, delete or erase any of the email item, which is not needed any longer
  • After this, open the Folder-List view
  • At the bottom side of Navigation pane, click on Folder-List icon. You may also press CTRL + 6 for this
  • Now, right click on the folder of Deleted Items once again the Navigation Pane
  • Then, click on Empty Folder. >> File >> Account Settings
  • Once it is done, hit on Data Files tab, click on the file that needs to be compacted
  • Next, click on Settings >> Advance tab>> Outlook-Data-File Settings
  • Hit on Compact Now and after this, Outlook-Data-File Settings
  • In this step, click on OK
  • There is no requirement of present Outlook once the compacting process of offline OST file is done
  • If you wish to delete any item, from offline and online folder do this:
  • Next, click on Settings >> Advance tab>> Outlook-Data-File Settings
  • Choose the item that needs to be erased
  • Then, press DELETE

There is no need to worry at all, even if this method also does not work. Users can opt for another trick in such scenarios.

Some More Information

In case, users are accessing Microsoft Exchange in Cached Mode, then only, the chosen folder can be erased from OST file. The emails on the server would be downloaded again to the offline OST data file on its next synchronization, if user chooses the folder in Folder-Options in Send and Receive Settings for the account of Exchange Server. During accessing Cached-Exchange-Mode, public folders are not synchronized by default. Moreover, if users choose to synchronize the public folder the size of Offline Storage Table may increase significantly. Now, let us move to other way to fix the issue without any difficulties in below mentioned section.

Alternative Way to Fix Outlook OST File Size Not Reducing

The above-mentioned manual approaches can be used, but these tricks come up with some drawbacks. Performing steps manually needs some technical knowledge as even a single wrong step may lead the data in danger. Even the data can be lost permanently. Therefore, it is recommended to opt for a third party tool. OST Splitter is one the best software, which can be used for this propose. This is application has the potential to split large OST files into smaller parts. It brings up many attractive features to make the entire the task simple and quick. In addition, the utility is designed all the editions of Windows Operating System. In case of any difficulty, users may contact the support team any time.

The Bottom Line

Outlook OST file size not reducing after archiving, has now become one of the emerging issues. It may create hurdle in between of the work in an organization. Moreover, whenever users search for any manual method, they find it tough to find any relevant solution. Ultimately, they have to go through different challenges. Keeping this in mind, we have discussed two manual approaches to fix this error. Apart from manual strategies, we have brought forth a trouble free resolution as well, which makes the entire task effortless.