How to Increase the Attachment Size in Outlook

When sending messages with attachments, you might have the situations that the attachment is too large and Outlook does not allow you to send them out. To increase the size of the attachment, please follow the steps below:

Step 1: Type "Regedit" in the search box on the taskbar, and click once it appears;

Step 2: Select "Yes" on the "User Account Control" pop-up that asks "Do you want to allow this app to make changes to your device";

Step 3: In the "Registry Editor" window, click "HKEY_CURRENT_USER";

Step 4: Follow the registry tree below to open the Outlook "Preferences" window if you have Microsoft Outlook 2016 installed;


- HKEY_CURRENT_USER\­Software\­Microsoft\­Office\­15.0\­Outlook\­Preferences for Outlook 2013;

- HKEY_CURRENT_USER\­Software\­Microsoft\­Office\­14.0\­Outlook\­Preferences for Outlook 2010;

Step 5: In the "Preferences" folder, open the file "MaximumAttachmentSize", or create one if you cannot find in the list. To create the file, please follow the steps below:

1. Click "Edit" in the "Registry Editor" window;
2. Click "New";
3. Select "DWORD (32-bit) Value" from the drop-down list;
4. Change the file name to "MaximumAttachmentSize".

Step 6: Open the file and type the maximum size in the "Value data" box;

Step 7: Click "OK" to close the window.

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