Rapid Solution to Tackle – OST File Has Reached Max Size

Anurag | January 8th, 2018 | Email Settings, User Management

Outlook OST files are the most important files in the Outlook email client that help the person to work and check emails in offline storage. It’s an offline folder file of MS Outlook that allows the user to work offline and synchronize any type of changes with the Exchange server as it connects. The ability to work offline is very important and useful for any client to if there is unreliable network connectivity. This Outlook OST sometimes reaches the reached maximum size due to which user can’t access the Outlook data and causes a huge problem. The outlook data file has reached the maximum size. To reduce the amount of data in this file storage help the user to get their files access easily. This could be easily performed through OST Splitter very easily.

So in this section, we will cover all possible ways to make you understand how to work with .ost File that has reached max size limit. Now, the Outlook data file has reached the maximum size 2016 or in any other version won’t be a problem anymore.

Outlook Maximum Size Reached – Reasons Behind Error

Outlook. ost has reached maximum size 2016, 2013, 2010 & 2007 errors occur due to several reasons. The occurrence of such this error causes the workflow hindrance. The reason behind Outlook OST has reached maximum size are:

  • The OST file or ANSI-encoded PST file gets bigger than the size limit or getting being overloaded to 2 GB size.
  • User’s Uni-code encoded PST file size getting bigger than the size limit- approaching 50 GB size limitation.
  • The registry policy in place, which might have changed the limits that are there by default causing this error: Default Outlook Profile.ost has reached the maximum size
  • The Outlook OST files being corrupted due to some malware activity causing to increase the size of the OST folder.

These common reasons behind the Outlook data file has reached the maximum size 2016 / 2013 / 20 10 and lower versions.


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Solution to Handle – Outlook OST Has Reached Maximum Size

The proper choice of the solution for a particular problem depends on to the type of scenario that is affecting Outlook data file. Following are some of the ways that can help in finding solutions to Outlook.ost has reached maximum size 2016/2013/2010/2007 errors. Also download the instant solution here.

Step 1. Determine Outlook File Data Type

  • Close all the Outlook program that is running
  • Pin to Start >> Control Panel
  • Then in Mail section, click on to Data File
  • Double click that particular Outlook data file If “MS Exchange” window shows up, then file is .ost
  • Now in “Advanced” tab
  • Click at bottom see the message that declares “Mailbox Mode” either as Unicode or as non-Unicode
  • If Personal Folders window comes up, then that file is PST file
    1. If value is “Personal-Folders-File (97-2002)”, then it is an ANSI format file
    2. If value is “Personal-Folders-File” then it’s clearly Unicode
  • Note the type

Step 2. Locate Outlook-Data-File
Outlook maximum size reached problem can be resolved if the user can locate the problem source. In order to get the problem p[lease ensure if there are no hidden files.
The ost files are located under this location – C:\Users\-your-username-here\AppData\Local\Microsoft\Outlook\

  • Now go to Tools in any of the Explorer windows
  • Then Folder Option-click on to View
  • Now select radio button to Show hidden files

If MS Outlook is in use with an MS Exchange server, then there would be 1 or more than 1 OST in this particular folder, else, there would be 1 or more than 1 PST files

Step 3. Convert Files to Unicode Format
ANSI-Encoded PST to UNICODE Format

  • Creating new Outlook profile to empty PST file
  • If version of Outlook is newer than 2003 then this new PST would be of Unicode format

Convert ANSI-Encoded OST File to Unicode Format

  • First Cached-Exchange-Mode has to be disabled
  • Rename OST file that is in question to this name “outlook.old”
  • And now, open Outlook
  • Close Outlook now and re-enabling Cached-Exchange-Mode

MS Outlook program would rebuild OST file in Unicode format along with data from MS Exchange server
This will solve the problem of Outlook 2016 OST has reached maximum size problem easily. The Outlook data file has reached the maximum size to reduce the amount of data in this file
max ost size outlook 2016 this method will help you to get rid of this problem.

Third-Party Software – A Hack Tip

This manual method is not safe to perform as deleting some important data file of Outlook can lead you to reinstallation of Outlook email client. Outlook.ost has reached maximum size could also be resolved with the help of an expert third party software SysTools OST Splitter Tool helps the user to split the large-sized OST files into smaller parts. You can get to see its demo model as well before finally buying the tool.


OST file has reached maximum size is a problem that occurs in Outlook 2016 / 2013 / 2010 / 2007 and below versions. Outlook 2016 maximum OST size can either be solved manually or with the help of a fast working tool.