PST Reached Maximum size-focus

When you open your Outlook, how do you feel when a message appears on the screen display “Your mailbox has reached the maximum size limit?”.

For all MS Outlook clients, it is definitely a head-scratching moment. However, this over-sized PST file could potentially lead to the corruption of PST files. Which results in losing the important data. So, don’t worry about losing the data this tech guide will help you to find the solution to this problem

Why PST Reached Maximum Size?

  1. MS-Outlook essentially stores information items from the mailbox in the PST format. However, they contain emails, notes, tasks, etc. Two types of PST files are supported by Outlook i.e ANSI and UNICODE. 
  2. The data file of Outlook has a specific data limit for the data items being processed. Outlook 97 to 2002 consists of 2 GB maximum size limit, and Outlook 2003/2007 consists of 20 GB maximum size limit. 
  3. If mailbox data crosses this limit then “PST reached maximum size” error occurs.

There are few more errors thrown by MS Outlook when PST files become oversized as shown below:

Reported Error 0x00040820:

While sending and receiving emails through a specific email account then this error occurs in Outlook 2010. Mailboxes crossed the maximum limit when a user attempts to synchronize mailboxes that crossed the maximum size limit.

Background Errors:

From one Outlook version to another when syncing of the mails takes place then this error occurs. It results in the size difference between the older and newer PST files.

File Access Error:

From one Outlook version to another when syncing of the mails takes place then this error occurs. It results in the size difference between the older and newer PST files.

How Can We Avoid PST Oversized File Issues?

An oversized PST file is mostly caused by more email items processing or attachments without including the file size limit that is 2 GB which is very small in Outlook 2002.

Nonetheless, due to comparatively higher allowable PST file size limits, it is unlikely that the PST file will suffer serious damage in the latest versions of Outlook.If users take note of the following measures, it is possible to avoid PST file corruption issues.

1. Delete Unwanted Stuff & Messages

There is a useless bit of data, attachments or emails that may not be needed for further reference or potential use. Analyze the data residing in your directories to save some storage space for new emails. Also, (press shift+delete on your keyboard) to delete unwanted stuff permanently.

2. Email Archives

To arrange same type of data in distinct folders to avoid huge loss of data in adverse situations or disaster scenarios, one must create an email archive.

3. Backups of PST Files

PST file backups need to be created so that the missing data can be retrieved easily and quickly in case you experience any PST corruption problems.

There are many ways to solve PST has reached maximum size error:-

1. Oversized PST Data-Clean Up

For deleting large PST file corruption, this is the fastest process. Cleaning data from PST files means removing all information that consumes unused space in the PST file. Data items that the client does not need should be deleted from the oversized PST file. 

To free up the PST file space, this is the easiest method. It prevents files from exceeding the maximum size limit. Duplicate data items in the PST file, if any are also deleted to free the extra space they occupy. This avoids the PST reached maximum size error.


  • Initially, Open your Outlook account.
  • Choose the non-essential data items.
  • Then, right-click and choose the option Delete.

If you want to migrate emails.

2. By Archive Method

  • Initially, Open your Outlook account.
  • Navigate the File Tab and choose the Archive option.
  • Browse Archive this folder option and click on it.
  • Move to section “Archive items older than” and specify a date.
  • Provide a path for the archived file, by clicking on Browse.
  • Hit the OK button, after giving all compulsory details.

3. Archive data in Outlook 2010/2013/2016/2019

  • Initially, Open your Outlook account.
  • Visit  File Tab.
  • Choose the option Archive under Cleanup Tools.
  • Select Archive this folder option.
  • Within the Archive items older than section, choose a date.
  • By clicking on browse option, choose the folders that need to be archived.
  • At last, hit on the OK button to start the retrieval process.

4. Archive data in Outlook 2007

The PST file for Microsoft Outlook 2007 has a file size limit of 20 GB. For the home user, this size is appropriate. Nonetheless, this file size is not appropriate for companies and they often face the error of' Outlook data file has exceeded the maximum size.

So, if the oversized PST file is not corrupted, then use the instructions below easily. Otherwise, if it is corrupted then manual data recovery is not possible for more information read more..


  • Initially, Go to the File tab.
  • From the list appears on the screen, select the Archive option. 
  • Next, choose the radio button corresponding to Archive this folder and all subfolders. Within the box “Archive items older than” specify a date.

Final Thoughts

All information from Outlook is stored in PST files. It is therefore also necessary to maintain the size of the PST file. When the total size of the PST file is reached, it becomes corrupted and unavailable. Follow the methods mentioned in the blog to stop Outlook files from transforming into an oversized PST file. As we have already discussed all manual ways to solve “Outlook PST reached maximum size” error.  

But once there are problems with massive PST file manipulation, it is impossible to get back the stored information objects. Turn to advance software to delete an over-sized PST file issue in such a case. Advanced tools help fix the error without any data loss.