Windows OS Hub
  • Windows Server
    • Windows Server 2022
    • Windows Server 2019
    • Windows Server 2016
    • Windows Server 2012 R2
    • Windows Server 2008 R2
    • SCCM
  • Active Directory
    • Active Directory Domain Services (AD DS)
    • Group Policies
  • Windows Clients
    • Windows 11
    • Windows 10
    • Windows 8
    • Windows 7
    • Windows XP
    • MS Office
    • Outlook
  • Virtualization
    • VMWare
    • Hyper-V
    • KVM
  • PowerShell
  • Exchange
  • Cloud
    • Azure
    • Microsoft 365
    • Office 365
  • Linux
    • CentOS
    • RHEL
    • Ubuntu
  • Home
  • About

Windows OS Hub

  • Windows Server
    • Windows Server 2022
    • Windows Server 2019
    • Windows Server 2016
    • Windows Server 2012 R2
    • Windows Server 2008 R2
    • SCCM
  • Active Directory
    • Active Directory Domain Services (AD DS)
    • Group Policies
  • Windows Clients
    • Windows 11
    • Windows 10
    • Windows 8
    • Windows 7
    • Windows XP
    • MS Office
    • Outlook
  • Virtualization
    • VMWare
    • Hyper-V
    • KVM
  • PowerShell
  • Exchange
  • Cloud
    • Azure
    • Microsoft 365
    • Office 365
  • Linux
    • CentOS
    • RHEL
    • Ubuntu

 Windows OS Hub / Outlook / How to Increase Attachment Size Limit in Outlook?

August 24, 2021 Microsoft 365Office 365Outlook

How to Increase Attachment Size Limit in Outlook?

There is a 20 MB limit on the maximum attachment size in the Outlook email client (including the latest versions of Outlook for Office 365 and Office 2019/2016). It doesn’t matter if a single large file or several small ones are attached — the total size of attachments would not exceed 20 MB.

When trying to send an email larger than 20 MB using Outlook, the following error message appears:

The attachment size exceeds the allowable limit.

The attachment size exceeds the allowable limit.

The file you're attaching is bigger than the server allows. Try putting the file in a shared location and sending a link instead.

outlook 365 error: The file you're attaching is bigger than the server allows. Try putting the file in a shared location and sending a link instead

If your email server and the recipient’s server support large email sizes, you can increase the maximum attachment size limit in Outlook.

Increasing the Maximum Attachment Size Limit in Outlook

You can change the maximum attachment size limit in Outlook only through the registry. There is no such option in the Outlook GUI.

  1. Close Outlook and open the Registry Editor (regedit.exe);
  2. Depending on your version of Outlook, navigate to the following registry key:
    • Outlook 2019/2016 and Outlook for Office 365 — HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Preferences
    • Outlook 2013 — HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Outlook\Preferences
    • Outlook 2010 — HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Outlook\Preferences
  3. Specify a new attachment size limit in the DWORD registry parameter named MaximumAttachmentSize. The value is specified in KB. For example, to increase the attachment size to 50 MB, specify here the decimal value 51200. By default, the attachment size limit is 20 MB (20480 KB). To completely disable the limit, change this value to 0; MaximumAttachmentSize Outlook registry parameter
    Note. If there is no MaximumAttachmentSize parameter in this registry key, create it manually: New -> DWORD (32-bit) Value.
  4. Create the MaximumAttachmentSize registry parameter with the same value in the reg key HKEY_CURRENT_USER\Software\Policies\Microsoft\Office\x.0 \Outlook\Preferences;
    You can set a limit on the size of Outlook attachments in the registry from the command prompt. For example, to set the limit of 50 MB for Outlook in Office 365, run the command:
    reg add HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Preferences\ /v "MaximumAttachmentSize" /t REG_DWORD /d 51200 /f
    reg add HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Profiles\Outlook\Preferences\ /v "MaximumAttachmentSize" /t REG_DWORD /d 51200 /f
  5. Close the Registry Editor and restart Microsoft Outlook.
You can centrally configure the attachment size in Outlook on users’ computers in the Active Directory domain by deploying a registry parameter through a GPO.

After the changes are made, you can attach larger files to your Outlook email (in our example, we have attached a 50 MB PST file).

Increase max attachment size Outlook 2013

If your or recipient’s email server doesn’t support large emails, you will receive an NDR (Non-delivery report) when trying to send a large email message from the Outlook or PowerShell script. This NDR will contain information that the maximum attachment size has been exceeded. Here are sample NDR messages you can get:

  • Attachment size exceeds the allowable limit
  • 552: Message size exceeds the maximum permitted
  • System Undeliverable, message size exceeds outgoing message size limit
  • The message was not sent; reduce the message size and try again
  • 552 5.3.4 Message size exceeds the fixed maximum message size
  • Error 0x80040610: The message being sent exceeds the message size established for this user
  • Maximum size of appendable message has been exceeded


If you send large emails only within your organization (local network), you can set any attachment size in Outlook. But most public email providers don’t accept emails larger than 25 MB.

The following table contains the maximum attachment size limits for most popular email services:

Mail serviceMaximum message size
Gmail25 Mb
Google Apps20 Mb (50 Mb for premier )
Microsoft Exchange Online (Office 365)25 Mb
Yahoo/ AOL25 Mb
Zoho Mail20 Mb

Attachment Size Limit in Exchange and Microsoft 365

In an on-premises Exchange Server, maximum email size limits are configured in several places (at the server, mailbox, and connector levels). You can view the current limits using the Exchange Management Shell:

Get-TransportConfig | ft MaxSendSize, MaxReceiveSize
Get-ReceiveConnector | ft Name, MaxSendSize
Get-SendConnector | ft Name, MaxMessageSize
Get-Mailbox maxbak |ft Name, MaxSendSize, MaxReceiveSize

In Exchange Online (Microsoft 365), you can set the maximum message size limit in the settings of each mailbox individually. You can check current limits through the Exchange Admin Center or with PowerShell. Connect to Office 365 using a remote PowerShell session or using the Exchange Online PowerShell v2 (EXO V2) module.

For new mailboxes, restrictions on the max size of incoming and outgoing emails are set in the plan settings:

Get-MailboxPlan | fl Name,MaxSendSize,MaxReceiveSize,isdefault

exchange online (microsoft 365) get maxsendsize limit

By default, Microsoft 365 has a limit of 35 MB for outgoing and 36 MB for incoming emails.

For a specific mailbox, you can view or change the limits for outgoing email as follows:

Get-Mailbox maxbak@woshub.onmicrosoft.com| fl MailboxPlan,MaxSendSize
Set-Mailbox maxbak@woshub.onmicrosoft.com -MaxReceiveSize 50MB -MaxSendSize 50MB

office 365: set maximum email size using powershell

If you mainly send emails with large email attachments only inside Microsoft datacenters, it is recommended to set the limit to 150 MB.

1 comment
3
Facebook Twitter Google + Pinterest
previous post
Fix: Windows Stuck at “Preparing to Configure Windows”
next post
Windows Server Core: Installing Active Directory Domain Controller

Related Reading

Fix: “Something Went Wrong” Error When Installing Teams

May 2, 2023

Send Outlook Emails Using Excel VBA Macro or...

April 11, 2023

Send from Alias (SMTP Proxy Address) in Exchange...

April 6, 2023

How to Use Plus Addressing in Microsoft 365...

April 5, 2023

Save Sent Items in Shared Mailbox on Exchange...

April 3, 2023

Categories

  • Active Directory
  • Group Policies
  • Exchange Server
  • Microsoft 365
  • Azure
  • Windows 11
  • Windows 10
  • Windows Server 2022
  • Windows Server 2019
  • Windows Server 2016
  • PowerShell
  • VMWare
  • Hyper-V
  • Linux
  • MS Office

Recent Posts

  • Configuring Event Viewer Log Size on Windows

    May 24, 2023
  • How to Detect Who Changed the File/Folder NTFS Permissions on Windows?

    May 24, 2023
  • Enable Single Sign-On (SSO) Authentication on RDS Windows Server

    May 23, 2023
  • Allow Non-admin Users RDP Access to Windows Server

    May 22, 2023
  • How to Create, Change, and Remove Local Users or Groups with PowerShell?

    May 17, 2023
  • Fix: BSOD Error 0x0000007B (INACCESSABLE_BOOT_DEVICE) on Windows

    May 16, 2023
  • View Success and Failed Local Logon Attempts on Windows

    May 2, 2023
  • Fix: “Something Went Wrong” Error When Installing Teams

    May 2, 2023
  • Querying Windows Event Logs with PowerShell

    May 2, 2023
  • Configure Windows LAPS (Local Administrator Passwords Solution) in AD

    April 25, 2023

Follow us

  • Facebook
  • Twitter
  • RSS
Popular Posts
  • Outlook Keeps Asking for Password on Windows
  • Checking User Sign-in Logs in Azure AD (Microsoft 365)
  • How to Manually Configure Exchange or Microsoft 365 Account in Outlook 365/2019/2016?
  • Whitelist Domains and Email Addresses on Exchange Server and Microsoft 365
  • Search and Delete Emails from User Mailboxes on Exchange Server (Microsoft 365) with PowerShell
  • How to Check Office 2019, 2016 and 365 License Activation Status?
  • Removing Built-in Teams Chat in Windows 11
Footer Logo

@2014 - 2023 - Windows OS Hub. All about operating systems for sysadmins


Back To Top