Increase OST File Size Limit in Outlook 2013, 2016, & 2010

Hello everyone in this Article I am going to describe about how we can increase OST file size limit for Outlook 2016 / 2013 / 2010 versions. Then default size of Microsoft Outlook 2010 / 2013 / 2016 is 50 GB for storing user data. We need to add some registry files to achieve this. So lets proceed to see the steps of increasing the size of OST File.

There are following registry files in which we need do some changes to increase OST file size limit.

• MaxFileSize
• WarnFileSize
• MaxLargeFileSize
• WarnLargeFileSize

MaxFileSize Registry: It defines the maximum file size limit for a PST file and does not allow to save more data after the defined limit.
WarnFileSize Registry: It defines the size limit at which Outlook starts giving warning message and stops downloading and saving any user data.

Edit Registry to Increase OST File Size Limit

Now we will see that which registry file should we edit to change the default OST file size limit for Outlook 2013 / 2010 / 2016.

Note: Before changing any registry file please take backup of all registry files by which you can restore it if something goes wrong during increasing OST file size default limit.

Lets proceed to see the steps:

1. Press Window key + R and type regedit in the textbox and hit OK button or you can also do it by searching through start menu.
2. Now click on + to expand My Computer and then expand HKEY_CURRENT_USER.
3. Now click on Software to expand it and then click on Policies too to expand it.
4. Then click on Microsoft for expanding it and then click on Office too to expand it.
5. Now expand 16.0 for Outlook 2016, 15.0 for Outlook 2013 and 14.0 for Outlook 2010.
6. Now click on PST and choose MaxFileSize from right side and click on Modify and then enter new value in the textbox and hit OK button.
7. For WarnFileSize, MaxLargeFileSize, and WarnLargeFileSize repeat same process defined in Step 6.

Note: The above way will work if the registry value is already created. What if the registry is not created? In this case you have to create registry manually.

Create Registry to Increase OST File Size Limit

1. Again go to Registry Editor by typing regedit in search of start menu or by pressing Window Key + R as we have discussed in editing registry steps.
2. Now in the same way as editing registry process go till Outlook after expanding 16.0 for Outlook 2016, 15.0 for Outlook 2013 and 14.0 for Outlook 2010.
3. Now right click by mouse button on Outlook and select New and then select Key and then type PST and hit Enter key to apply.
4. Now again right click by mouse button on PST and select New and then select DWORD (32 bit) Value and type MaxFileSize and hit Enter key two times to apply the changes.
5. Now in Edit Dword Value select Decimal radio button and in the Value data text box type the new file size limit in bytes and press OK button to apply.
6. Now keep repeating the value from step 3 to 5 for WarnFileSize, MaxLargeFileSize, and WarnLargeFileSize. After completion of these steps for all then close the registry editor window.

Conclusion

In this article we have discussed about how to increase OST file size limit in Outlook 2013, 2016 & 2010. We saw that it was not very difficult task to achieve, it was just work of some simple steps but it was little bit risky task because you are dealing with registry files. If something goes wrong then the computer might now work properly. Therefore i have recommend you to take backup of registry file first before editing it, by which you can restore it in case of any error.