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Outlook Mailbox Size Limit Exceeded – Four Solution to Fix It

Shini Mohan ~ Modified: 08-Sep-2021 ~ Outlook ~ 5 Minutes Reading

It is very common for Outlook users to encounter an Outlook mailbox size limit exceeded issue. Generally, this error occurs when the Outlook mailbox reaching its storage limits. So to inform the users the Outlook display this error message.

Also, there are some users who not getting this warning message but they are facing the performance issue while using Outlook. And the reason behind the degradation of Outlook is the oversized Outlook mailbox. As we know that Outlook gives certain file size limits such as in Outlook 2002 and older 2 GB, in Outlook 2007 20GB, and in Outlook 2019 50 GB.

Therefore, after considering the user’s queries about the degradation of Outlook performance and size limit warning on various forums. Here we have come up with the solution that surely helps users in order to resolve the issue of Outlook mailbox size limit exceeded error.

But before starting the fixed part let’s see what are the reasons for this issue

Reasons for Oversized Outlook Mailbox

There are various reasons responsible for this issue some of the major ones are listed as below:

  • Running Exchange Server and have set the mailbox size limit
  • Using older version Outlook
  • Duplicate Item in Outlook Mailbox
  • Having huge numbers of attachments in Outlook mailbox

How to Resolve Outlook Mailbox Size Limit Exceeded Issue?

Solution 1: Delete Duplicate Items from Outlook Mailbox

We know that the duplicate items consume the same amount of space as original ones. However, Outlook has a history to receive duplicate items such as email contacts calendar task notes, and journals. So to resolve the Outlook mailbox size limit exceeded issue you can use an inbuilt utility called the Cleanup. To use CleanUp utility follow the below steps

  • First, launch Microsoft Outlook on your Windows PC.
  • Click on the info option and then the cleanup tool.
  • Now choose the mailbox cleanup option.
  • After that select the view mailbox size option to scan the mailbox size along with all subfolders.
  • Now select the option to find a bigger or older email that you can delete directly from the cleanup.

The cleanup utility is a nice approach but it is effective only if you have a fewer number of items in your mailbox. The message that no duplicate items found in the mailbox. so so in that situation, you can try a third-party solution that is SysTools Outlook Duplicate Remover. The tool is very effective with removing duplicate from Outlook, it removes duplicate emails, contacts, calendars, contacts, task, notes, and journals. Also, it is capable to save data integrity while deleting duplicate items from Outlook.

save outlook attachments to folder

Solution 2: Update Outlook Version

Using an older version of Outlook is also be the reason for the Outlook mailbox size limit Exceeded error. So check if the Update is available for you Outlook then update it. To do this follow the below steps.

  • Launch Outlook and click on the File
  • Choose Office Account
  • Select Update Option and then Update Now
  • If an update is available then it starts automatically

Solution 3: Increase Mailbox Size Using Registry Entries

Users can increase the size of Outlook mailbox making a change in registry settings. To do this follow these steps:

  • Press the Window + R button to open the Run dialog box
  • Type Regedit and press enter then click on the enter button
  • In Registry Editor expand the Computer folder
  • Click on the HKEY_CURRENT_USER folder contents will get displayed in the right-hand
  • Go to the following registry path

For Outlook 2007: HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\12.0\Outlook\PST

For Outlook 2010: HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\14.0\Outlook\PST

For Outlook 2013: HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\15.0\Outlook\PST

For Outlook 2016: HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\16.0\Outlook\PST

  • Now double click on the PST folder, and you will see two values
  • Click on the MaxLargeFileSize or WarnLargeFileSize value in the list and enter the data value in MB
  • Now click on the OK button and then exit from the Registry Editor settings
  • Once the setting is done restart the computer to save the settings

Solution 4: Export Outlook Attachments

If you are getting a huge number of attachments on the daily basis, then a certain period of time you will notice that your Outlook mailbox is filling very fastly. So to avoid this issue you can export all the attachments from Outlook to your desktop. To do this you can use the Save All Attachments option. But this manual process is a bit slow and you have to save each attachment one by one from Outlook emails.

save outlook attachments to folder

So, if you don’t want to waste your time, then you can try the SysTools Outlook Attachment Extractor. This toolkit is capable to export multiple attachments from Outlook in bulk and helps you to get rid of the Outlook mailbox size limit exceeded issue. Also, the tool is capable to save attachments from Outlook email, contacts, calendars, tasks, and journals.

The Ending Notes

The above post outlined the causes of the Outlook mailbox size limit exceeded issue. Also, we have discussed the top four methods to resolve this issue. So go through the blog and resolve the issue without losing any data.