How to Increase Outlook Data File Size Limit (PST & OST)?
Running out of space in Outlook? The default PST and OST file size limit can quickly fill up if you receive emails with large attachments. This guide explains how to increase Outlook data file size limit using the Windows Registry Editor, archive old emails, compact Outlook data file, divide your large data files, change “Mail to Keep Offline” setting, and other methods.
Along with that, you’ll learn the default size limits for each Outlook version and how to safely modify the registry entries (MaxFileSize, WarnFileSize, etc.) to expand the capacity of your Outlook data files without any data loss, other manual techniques, or drawbacks.
There are various cases when you need to increase Outlook data file size limit beyond the default size available. If you receive lots of emails a day with larger attachments, it can result in size limit issues. Here in this blog, you can see the complete process one by one.
Let’s understand the file size of Outlook data files according to versions for better understanding:
- Outlook 2002 & earlier – 2 GB (ANSI – Cannot be increased)
- Outlook 2003–2007 – 20 GB (UNICODE – Maximum 50 GB)
- Outlook 2010–2021 – 50 GB (UNICODE – Maximum 50 GB)
- Microsoft 365 – 50 GB (UNICODE – Maximum 50 GB)
Can You Really Increase Outlook Data File Size?
Yes, you can increase outlook pst size limit within Microsoft’s allowed range. Microsoft allow users to increase the maximum size of PST and OST files by modifying Windows Registry values and other methods. But these techniques don’t improve Outlook performance and contains high risk of corruption. You can use automatic tools according to your reequipments. These are the techniques to increase Outlook PST size limit:
- Windows Registry Editor
- Archive Old Emails
- Divide Data Files
- Compact Outlook Data File
- Change “Mail to Keep Offline” Setting
- Delete & Rebuild OST File
Method 1: Windows Registry Editor to Increase Mailbox Size
This is the perfect method to increase Outlook data file size just by changing the registry. Follow the mentioned steps one by one:
Important Note: Microsoft doesn’t support to increase Outlook PST size limit using the Registry, because it contains a high risk of corruption.
These are the four registry entries that allow you to limit the size of Outlook .PST and .OST files:
- MaxFileSize registry entry – It determines an absolute maximum size for .PST and .OST files, up to which they can grow. The Outlook does not permit the size of the data file to grow beyond this maximum size.
- WarnFileSize Registry Entry: It determines the maximum data an Outlook data file can have. When this maximum data is reached, the Outlook .PST or.OST files are not permitted to add any more data. But there can be an increase in the physical file size because of internal processes.
- MaxLargeFileSize Registry Entry: To set the maximum size up to which an Outlook data file can be expanded (only for UNICODE files).
- WarnLargeFileSize Registry Entry: To set the maximum allowable data for Outlook data (PST / OST) file (only for UNICODE files).
Important: Incorrect registry changes may cause system instability. Make sure you have a backup copy of your data file before proceeding to increase Outlook data file size.
- Choose “Windows + R” and type “regedit” and hit the “Enter” button.
- Now, find the Outlook version key:
HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\PST
(Replace 16.0 with your Outlook version) - Right-click on the >> New >> DWORD (32-bit) Value.
- Next, create these entries:
Outlook Version Policy location for registry entries in Registry Editor MaxLargeFileSize Maximum PST/OST size WarnLargeFileSize Warning threshold - Now, set the values in Decimal (MB):
- And finally, restart your Outlook account.
Limitations:
- Increasing the Outlook data file does not improve performance.
- These methods increase the risk of corruption of data files.
- Microsoft does not recommend exceeding reasonable limits.
Method 2: Divide Large Data Files
If your Outlook mailbox is full and contains your crucial data. In simple words, you don’t want to lose any data, so use the SysTools PST Splitter Tool. This software allows users to split PST file into smaller parts of MB, GB, and TB. It’s the best option to increase Outlook PST size limit without removing or deleting any data. Also, there is no risk of corruption and data loss, because it keeps your data separate and managed. Download the free edition now:
How to Increase PST File Size?
- Download and run the solution.
- Add your files/folders using the given options.
- Select the location to save the file using the Browse icon.
- Choose Options as per choice.
- Protect your data file and choose the Split icon.
Method 3: Increase Outlook Data File Size by Archiving
If your goal is to manage and organize your data, then archiving would be the best option for you. You can archive and keep your crucial emails and data safe for future access:
- Head to the “File” tab in Outlook.
- Choose “Tools” >> “Clean Up Old Items” options.
- Select a folder that you want to archive.
- Select any date according to your requirement.
- After that, choose location and save the archive PST file.
- Finally, select the OK button to increase Outlook data file size.
Limitations:
- This method creates multiple PST files.
- You can’t search anything within the file until it is opened.
- It doesn’t archive your OST file data.
Method 4: Compact PST/OST Data Files
Compacting Outlook data files means it removes the extra space from the PST/OST data files.
- Open your Outlook account.
- Choose the “File” >> “Account Settings” > “Data Files” options.
- After that, select the “PST/OST” file.
- Choose the “Settings” >> “Compact Now” options.
Drawbacks
- It doesn’t increase Outlook PST size limit.
- Time-consuming process for large data files.
- Minor reduction for heavily used files.
Method 5: Increase OST File Size by Changing “Mail to Keep Offline”
This technique helps to reduce OST file size, especially for Microsoft 365 and Exchange users.
Important Note: This method only downloads recent emails instead of the full mailbox.
- Choose the “File” tab in Outlook.
- Choose the “Account Settings” option.
- Select the “Exchange/Microsoft 365” account.
- Hit the “Change” icon.
- Adjust the “Mail to Keep Offline slider” (e.g., 6 months).
- Now restart your Outlook to increase Outlook data file size.
Method 6: Delete and Rebuild OST File
- First, close your Outlook completely.
- Choose the OST file location.
- Delete or rename the OST file.
- Restart your Outlook account.
- And finally, Outlook will create a new OST file automatically.
Limitations
- Required a stable internet connection.
- A large mailbox will take a long time to resync.
- Not suitable for PST file.
Method 7: Duplicate Emails
If your mailbox is filled with duplicate emails, and you are not able to remove them, then download the SysTools Outlook Duplicate Remover Tool. This is the best solution, which allow remove and save them locally according to your choice. Users can remove duplicates from Mail, Calendar, Tasks, Contacts, Journal, and Notes. Download the free demo versions.
How to Increase Outlook PST Size Limit?
- Download and start on your system.
- Add your data files and folders.
- Choose between “Within Folder(s)” and “Across Folder(s)” options.
- Select the folders according to your needs.
- Choose the “Filters” as per your choice.
- Choose “Data Range” to export selective data.
- After that, select the “Action” as needed.
- Finally, select the “Next” and “OK” buttons.
Best Practices to Avoid Outlook Size Issues
Here are some best practices to avoid the large mailbox size issue:
- Keep your PST/OST file under control.
- Archive your old emails regularly.
- Try to avoid keeping your large attachments.
- Compact your data files periodically.
- Use multiple PST files instead of one large file.
What if the PST File Get Corrupted?
The Microsoft Outlook PST file becomes damaged and inaccessible due to recurring PST corruption issues. One major reason for PST file corruption is overwriting a PST file due size limitation problem. But in the latest versions, users face the same problem. The only way to fix an increased Outlook data file size issue. SysTools has a leading solution for resolving Outlook PST file issues. The Outlook Recovery Software can fix highly corrupted data files. Download the software, scan, and repair Outlook PST file in a few simple steps.
A PST data file can be corrupted by multiple reasons. The oversized PST file issue is only one among them. But the software suggested above a help to fix PST data issues irrespective of the cause. It is an all-in-one solution for MS Outlook users.
Let’s Conclude
If you frequently deal with large mailboxes, increasing the Outlook PST file size limit through registry modification, archiving old emails, dividing data files, compact Outlook data file, change “Mail to Keep Offline” setting, and delete & rebuild OST file are the best techniques.
You can use an automated solution as well to divide your large data files and remove duplicate emails according to your needs. You can select any technique as per your requirements. For any query, you can contact us through chat support.