This article discusses the way to configure Outlook PST File size limits manually to fix issues like the dearth of space for new incoming messages.

Do you know the default maximum size limit for your Outlook PST file? Most of the Outlook users do not even consider it important. But, when users realize that there is an issue while sending or receiving emails, they need to know the default or specified size for the PST files by them. It could be the reason that the storage space has reached the maximum set value for the PST files. You can verify the set PST file size limit for your Outlook application.

When the maximum limit is reached, when you try to move the Outlook file items, you might receive this error:

Can't move the items. The file > path > \ > filename > .pst has reached its maximum size. To reduce the amount of data in this file, select some items that you no longer need, and then permanently delete them.

Deleting Outlook file items manually would be a cumbersome task. Users need to search for another solution, like increasing the maximum size limit.

For Outlook versions older than 2010 version, the default maximum recommended Outlook PST file size is 20 GB and for Outlook 2010 & above versions, the default maximum recommended size for Outlook PST file is 50 GB.

Now, the question is ‘Can this default maximum PST size be expanded?’. The answer is Yes. For example – You can raise the Outlook PST file size for latest versions from 50 GB to 100 GB. This is done by editing the registry entries.

  • MaxLargeFileSize - This registry entry can be used to set the maximum size up to which Outlook PST file can expand (for UNICODE format PST files).
  • WarnLargeFileSize – This registry entry can be used to set the maximum allowable data for Outlook PST file (for UNICODE format PST files).
  • MaxFileSize – Works like MaxLargeFileSize registry entry, but for ANSI format PST files (earlier Outlook versions file format).
  • WarnFileSize - Works like WarnLargeFileSize registry entry, but for ANSI format PST file.

Now, let us perform the manual way of using these registry entries to configure Outlook PST file size limits.

Manual Process To Configure PST File Size Limit in Outlook

  1. Open Registry Editor Close your Outlook application. Open Run dialogue box by pressing the Windows button and R alphabet together. Then, type regedit and click OK to open the Registry Editor.
  2. Locating the PST File
    In the opened Registry Editor application, reach the following location for different Outlook versions.
    • MS Outlook 2003:
    • MS Outlook 2007:
    • MS Outlook 2010:
    • MS Outlook 2013:
    • MS Outlook 2016:
  3. Creating DWORD Values Now, on the left panel, right click on the blank space and then select New > DWORD (32-bit) Value.
  4. Provide the registry name as MaxLargeFileSize
  5. Adding File Size Limit Right-click on the created DWORD Value and click Modify. Here, select the Decimal option as Base and enter the value as per your requirement. The value which you enter is in MB. (we have entered 75 GB here by calculating 1024*75 = 76800MB). Click OK.

Likewise, you can create DWORD value WarnLargeFileSize and assign value to it. The recommended size is 95% of the set Mailbox File Size Limit. For example, consider 70GB here.
1024*70 = 71680MB

For ANSI Format files, use registry values as MaxFileSize and WarnFileSize. Note that you need to enter values in Bytes if chosen Decimal as the base. Here, the recommended default size is 1.8 GB only which you can expand up to 2GB only, otherwise the value will be ignored to avoid any corruption issue.

Reduce the actual mailbox and PST file size

The more you use the Outlook account to send and receive emails, the faster your mailbox increases in size and reaches to its maximum limit. The users understand that the large mailboxes are slower in responding to the queries. But the PST file may not reduce in size automatically, but Outlook has given some methods to shrink it to accommodate more emails.

Mailbox Cleanup Tool

A Mailbox Cleanup tool is present in Outlook that allows you to view the size of the mailbox and the individual folders. You can use it wisely to search the older email messages that are large but do not require now. Many times, the deleted email messages keep occupying the mailbox space, increasing its size. The mailbox cleanup tool lets you check the deleted emails and delete them directly. Here is the process;

  1. Go to the File menu in Toolbar. Then go to Tools drop-down and choose Mailbox Cleanup. Go to the File menu in Toolbar
  2. After opening the Mailbox Cleanup tool, you can see the multiple options of Viewing mailbox size, finding the older items, AutoArchive at a regular interval, emptying the deleted items folder, etc. You can use all these options to remove unwanted content and reduce the mailbox size. options to remove unwanted content and reduce the mailbox size
Compact the Outlook PST file

The compact method to reduce the PST file eliminates the whitespace in the PST file.

  1. Follow File > Account Settings > Account Settings. Follow File > Account Settings > Account Settings
  2. In the Data File tab, choose the data file that you want to compact and click Settings. compact and click Settings
  3. Click the Compact Now button, and Outlook will compact the data file. This process will take some time for a large-sized file.

How to fix Outlook PST corruption due to large file size?

So, as you have read, it is not a complicated task to configure Outlook files size limits through registries. However, a certain amount of focus and little technical expertise is always needed. And if you set values much beyond the limits, then corruption of PST files could be the result. For users facing PST corruption after attempting this method or already suffering from any PST related issue, we would suggest you trust Kernel for Outlook PST Repair tool. This tool has all the features needed for quality PST solution. Simple GUI and intelligent filters are its highlights. Get a live trial with its demo version on the website.