By default, the maximum size for outgoing emails, which includes the message and any attachments, is set at 50 MB.


However, you might occasionally see the following error in Outlook, even if the attachment is under 30 MB:


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The file you're attaching is larger than what the server permits. Consider placing the file in a shared location and sending a link instead.

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This error message appears because Outlook 2013 and subsequent versions impose a default attachment size limit of 20 megabytes (20480 KB) for Internet email accounts. 

This restriction is intended to prevent your computer from continuously attempting to upload very large attachments that surpass the limits set by most Internet service providers.


The article below outlines the steps to adjust the default attachment limit based on the type of email account you are using with Outlook.


To change the default attachment size limit in Outlook for an Internet email account, follow these steps:



1. Close Outlook.


2. Open the Registry Editor.


3. Find and select one of the following registry subkeys:


HKEY_CURRENT_USER\Software\Microsoft\Office\<x.0>\Outlook\Preferences

HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\ x.0 \Outlook\Preferences


 Note


  • The <x.0> placeholder corresponds to your Office version (16.0 = Office 2016, Office 2019, Office LTSC 2021, or Office 365; 15.0 = Office 2013).
  • Create the path in the registry manually if it does not already exist.



4. Add the following registry data under this subkey:


Value type: DWORD

Value name: MaximumAttachmentSize

Value data: An integer specifying the maximum allowable attachment size. For example, set it to 30720 (Decimal) to establish a 30-MB limit.


 Note


  • Set a value of zero (0) to impose no limit on attachments.
  • Choose a value less than 20 MB if you wish to set a limit lower than the default 20 MB.



5. Close the Registry Editor.


6. Launch Outlook.