Quickly increase or change maximum attachment size limit in Outlook

Kutools for Outlook

In Outlook, when you adding an attachment exceeding 20 MB - the default maximum attachment size limit - Outlook will warn you with information as below screenshot shown in Outlook 2013 or later versions. Kutools for Outlook’s Maximum Attachment Size option can quickly increase or change the maximum attachment size limit as you want.
shot increase attachment size 1

Change maximum attachment size to unlimited
Increase maximum attachment size as you need

Change maximum attachment size to unlimited

With Kutools for Outlook’s Maximum Attachment Size option, you can set the maximum attachment size to no limited.

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1. Enable Outlook, and click Kutools > Options. See screenshot:

2. Then in popping Options dialog, under Others tab, type 0 into the textbox under Maximum Attachment Size. See screenshot:

3. Click OK, a Kutools for Outlook dialog reminds you to restart Outlook program for the new setting. See screenshot:

4. Click OK to close the dialog, and restart Outlook. Now you can add attachments without any size limited in massages.

Note: If you want to change the maximum attachment size to default setting, just type 1 into the textbox next to Maximum Attachment Size.

Increase maximum attachment size as you need

If you just want to increase the limited maximum attachment size while inserting attachments in messages, you can do as these steps:

1. Enable Outlook, click Kutools > Options. See screenshot:

2. And under Others tab of the popped out dialog, type the new maximum attachment size you want into the textbox under Maximum Attachment Size. For instance, here I increase the maximum attachment size to 30 MB by typing 30720 into the textbox. See screenshot:

Tip: Here the unit of the attachment size is KB, if you want to change the maximum attachment size to X MB, you just need to type the number = X * 1024.