How to increase the file size limit of Outlook attachments

When working with the Office suite of Microsoft Office, you will be no stranger to the Outlook mail platform anymore. In this article I will share with you how to fix the Outlook Mail attachment size limitation on Windows 10, so you can attach larger files!

1. What is Outlook attachment size limit?

During use, sometimes you will have the need to send a document file or something (called attachments) to others by email instead of chat platforms.

Simply because the chat platform they are born not to do this, and the security issue can not be as good as Email.

Attachments cannot be too large because Mail server usually only allows sending files up to 25 MB, but that figure with Microsoft's Outlook on Windows 10 is even more modest, only 20 MB only.

So in the process of using, sometimes you will receive a message that you cannot send mail because the size of the attachment exceeds the allowed 20 MB.

So I encourage you to follow this guide to increase the Outlook attachment size limit to 25 MB, equal to the Mail Server's limited capacity to avoid sending mail and many other troubles. in use.

Yes, the instructions below will be applicable to most versions of Outlook today: Outlook 2019, Outlook 2016, Outlook 2013, Outlook 2010 and Outlook 365….

2. How to increase the Outlook attachment size limit on Windows 10

To do this, we need to use a fairly familiar tool Registry Editor, you do the following:

+ Step 1: First of all, open the dialog box RUN (Windows + R) => then type the command regedit => and press Enter to access Registry Editor on Windows 10.

You can use other ways to open Registry Editor if it is more convenient, but in my opinion this is convenient and fastest possible.

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+ Step 2: Then, access Outlook's Preferences folder in the Registry by the path below:

ComputerHKEY_CURRENT_USERSOFTWAREMicrosoftOffice16.0OutlookPreferences

NOTE: For Outlook 2019, you can directly paste the path above into the Registry Editor's address bar for faster access. Paths to the Preferences folder for older Outlook versions in the Registry will be:

1. Office 2016, 365: Similar to Outlook 2019
2. Office 2013: ComputerHKEY_CURRENT_USERSOFTWAREMicrosoftOffice15.0OutlookPreferences
3. Offce 2010: ComputerHKEY_CURRENT_USERSOFTWAREMicrosoftOffice14.0OutlookPreferences

Look in this Preferences folder for a DWORD key named MaximumAttachmentSize => then right-click and select Modify… to change its value.

=> This is the key that specifies the value limit for the attached file size of Outlook on Windows 10.

If you can't find it, don't worry, just right-click and choose New => DWORD (32-bit) Value to create a new key and name it MaximumAttachmentSize.

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+ Step 3: Double click on the MaximumAttachmentSize key you just created.

The default value (even when the MaximumAttachmentSize key does not exist) is 20480KB, which is equal to 20 MB as mentioned above.

We will fix it to 25 MB in accordance with the Mail Server attachment size limit, in this case the Registry uses KB instead of MB or GB as usual, so you can not enter the number 25 directly. OK.

First you have to convert the number of MB you want to KB, 1 MB = 1024 KB, so 25 MB would be 1024 x 25 = 256000 KB, that's simple.

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Alternatively, you can also set the value to 0 if you want to remove the file size limit for attachments, but this is not recommended since all Mail Servers have already set the size limit, so if If you send too much, you still have an error that cannot be sent as usual.

Now go back to the value editing window in Registry Editor, switch the data type from Hexadecimal to Decimal, enter the Value Data box the value you want in KB, I want 25 MB, so you will enter 25600 as already. Calculated above then OK to save is finished.

=> Finally, remember to restart your computer when possible to let these changes take effect.

3. Conclusion

Yes, so I have just finished showing you how to increase the Outlook attachment size limit on Windows 10.

This is a rather annoying problem because I use Outlook on Windows to manage all Email and regularly send / receive messages, often have to exchange documents so it causes a lot of trouble for me.

Hopefully this trick will also help anyone who is having problems similar to me. Good luck !

Isabella Humphrey

Update 26 February 2021