How to Compress OST File in Outlook?

Facing problems while handling your OST file in Outlook? If the problem is related to the file size of the OST file, compressing the file is one of the basic functions of the Outlook email client account.

This article intends to provide users with effective methods to Outlook compress OST and tricks that will help you manage your OST files with perfection.

Method 1: Changing the Settings of “Mail to Keep Offline”

The option holds significance for Microsoft Outlook users that utilize it in the case of the availability of internet connection. Users can easily synchronize their data according to a set requirement. The control in the extent of synchronization allows them to manage the important information within the file.

Note:This can only be achieved through the use of the "Mail to Keep Offline" option according to the settings affirmed by the user.

Achieve this by following the steps below:

Step 1: Open your Outlook account and proceed to the “File” tab on the top of the screen. Click on the “Info” button present on the next screen.

Step 2: You will find the option of “Account Settings” across the Info menu. Proceed further by clicking on the “Account Settings” option that appears further in the menu. Tap on the profile icon to choose the option of “Change.”

access account settings

Step 3: You will be provided the slider of "Mail to Keep Offline" on the next screen. Adjust the setting between 3 days to 5 years for the reduction of the size of the OST file. You can significantly change the time scale for managing the size of the OST file.

use slider to set time period

Method 2: Reducing the File Size of OST File to Make it Compact

The next solution involves the accessibility to the options of reducing the Outlook OST file. Microsoft Outlook accompanies its users to Outlook compress OST by means of compacting data.

There are no particular losses of data across the file; however, it is only made compact through compressing.

Its execution is completely based on removing unwanted items across the account and making space through deletion. Look into the steps to know more about the process:

Step 1: You need to direct yourselves into the “File” tab after opening the Outlook account. Select the option of “Account Settings” across the Info section on the next screen. You will find the option of “Account Settings” in the drop-down menu ahead.

tap on account settings option

Step 2: On the window that appears on the screen, you need to direct into the “Data Files” tab and select the OST file that you wish to compact.

choose your ost file

Step 3: Open the OST file settings by clicking on the "Settings" option. Proceed to the "Advanced" section.

access advanced tab

Step 4: You will find the option of “Outlook Data File Settings” on the next screen that will be used for compacting data. Click on “Compact Now” and proceed for confirmation. The file size of the OST will be reduced to compact data across it.

apply compact feature

Method 3: Cleaning Up the Mailbox

When the question comes to an understanding of how to compact the OST file, you should look to your mailbox for cleaning up storage to compress the file size for more information. The professional field demands huge file sizes, which can only be achieved through the execution of smart means. Compressing the mailbox is equivalent to reducing the older messages across the email client. This can help the user in tackling the issues in their file sizes, which is covered with the following steps:

Step 1: Proceed into the “File” tab from the top of the screen of Outlook. Click on “Info” and find the option of “Cleanup Tools” in the list. Click on the menu to use the “Mailbox Cleanup” option.

select mailbox cleanup option

Step 2: With the new screen opened, click on "View Mailbox Size" to check the overall size of the OST File that is connected with your Outlook email client.

view your mailbox size

Step 3: With the help of the “Find” button across the same screen, you can search for the older items by including days or file sizes in the search.

find your items using filter

Step 4: Look through the options of "Empty Conflicts," "View Deleted Items Size," and "Find items larger than" for deleting the unwanted data from the OST file.

Method 4: Sharing Information through Shared Folders

Microsoft Exchange account is known for the variety it upholds in providing users with the options of synchronizing their data. People are allowed to manage their information and data with other Exchange accounts through the aid of “Shared Folders.” This, however, does not provide any source of help in managing the size of the OST file.

Since they take up considerable space of the OST file, they require to be disabled. To disable the “Shared Folders” synchronization and Outlook compress OST, you need to look across the following steps:

Step 1: Open Microsoft Outlook and lead into the ‘File’ tab. Click on “Account Settings” and proceed by clicking on the option of “Account Settings” across the drop-down menu.

open outlook account settings

Step 2: With numerous tabs displayed on the screen, click on “Data Files” and explore the tab for choosing the OST file that you want to reduce.

choose the ost file

Step 3: Open "Settings" of your Outlook email client. Proceed to the "Advanced" option and disable the button "Download Shared Folders." Restart the Outlook account to re-synchronize the files.

disable download shared folders option

Method 5: Set Up Archive Folder to Compact Data

Since you are searching for methods to Outlook compress OST, this feature holds significance in controlling the data flow of your OST file.

An archive folder can help you maintain and save your data across the computer by transferring important content from the main mailbox.

Note: Its existence helps users in controlling the size of the OST file while making sure that no data is deleted or removed from the account.

To set up an archive folder, look through the following steps for a better understanding of the process:

Step 1: Navigate to the “File” tab on the top-left corner of the screen and click on the "Info" section. Find the "Cleanup Tools" button in the list and open the option of "Archive" by clicking on it.

choose archive cleanup tool

Step 2: A window opens up on the screen. Proceed to select the files and folders that are to be archived in the process. Set the location for the folder that will be archived and click on "OK" to create an archive folder for your Outlook account.

finalize the archive file items

Method 6: Preset File Size Limits With the Help of Registry Key

File sizes can be controlled through multiple techniques. However, if the user is looking for a direct approach that answers the question of how to compact OST file, they should consider going for the Registry Key. By modifying the values and entries of the specific platform, there would be no requirements for removing the previous or older mailbox items from the computer. Users can easily decrease the sizes of their files without proceeding toward deletion.

This method is collectively covered with the aim of changing the maximum size of the registries, which automatically sets up space for more content across OST files. There are four registry entries that can be consumed during the process. The "WarnLargFileSize” and “MaxLargeFileSize" are two entries that consume the UNICODE format, holding a file size of 50GB for Outlook 2010 and later versions. It supports 20GB of data for Outlook 2003 and 2007.

On the other hand, the registry entries of “MaxFileSize” and “WarnFileSize” utilize the ANSI format with a limit of 2GB for Outlook 2000 users. Look through the provided tables for more comprehensive information:

For Outlook 2010,2013, and 2016

Name

Type

Valid Data Range

Default

MaxLargeFileSize

REG_DWORD

0x00000001 – 0x0000C800

0x0000C800 51,200 (50 GB)

WarnLargeFileSize

REG_DWORD

0x00000000 – 0x0000BE00

0x0000BE00 48,640 (47.5 GB)

MaxFileSize

REG_DWORD

0x001F4400 – 0x7C004400

0x7BB04400 2,075,149,312 (1.933 GB)

WarnFileSize

REG_DWORD

0x00042400 – 0x7C004400

0x74404400 1,950,368,768 (1.816 GB)

For Outlook 2003 and 2007

Name

Type

Valid Data Range

Default

MaxLargeFileSize

REG_DWORD

0x00000001 – 0x0000C800

0x00005000 20,480 (20 GB)

WarnLargeFileSize

REG_DWORD

0x00000000 – 0x0000BE00

0x00004C00 19,456 (19 GB)

MaxFileSize

REG_DWORD

0x001F4400 – 0x7C004400

0x7BB04400 2,075,149,312 (1.933 GB)

WarnFileSize

REG_DWORD

0x00042400 – 0x7C004400

0x74404400 1,950,368,768 (1.816 GB)

Bonus: Convert Your OST to PST File Format Using Stellar Converter for OST

Another great approach that can be considered for the objective to Outlook compress OST is by converting the OST file into PST. Since the data that is present across your mailbox is extremely important and cannot be deleted in any case, you can surely proceed to convert it into a PST file for saving it for late purposes. Stellar Converter for OST holds great precedence in helping users to execute this process.

The tool is known for its simple and effective interface, with an environment that is controlled by all means. It provides users with the option of managing the deleted content across their OST file in the preview window. Along with that, it also converts the file in the easiest way possible.

stellar converter for ost to pst

Conclusion

Are you aware of the methods that can effectively help you to Outlook compress OST? This article features some of the best techniques that will provide you with the opportunity of managing your OST file and make the process simpler and manageable for you amidst the professional life that you are entangled in.