In theRundialog box, typeregedit.
Navigate the registry tree and go to the entry corresponding to your Outlook version:
Double-click theMaximumAttachmentSizevalue.
If you don’t see MaximumAttachmentSize,add a registry key and value.
Go toEdit, selectNew>DWORD Value, enterMaximumAttachmentSize, and pressEnter.
In theValue datatext box, enter the desired attachment size limit in KB.
You may be confused that 25600 KB equals 25 MB.
That’s because regedit uses a different measurement system than you may be familiar with.
Because of these differences, regedit uses 1024 KB to equal 1 MB.
So, the equation to determine the decimal number depends on the MB of storage you want to use.
In this case 25 MB is: 25 x 1024 KB = 25600 KB.
If your email server allows larger attachments, instruct Outlook to send messages larger than 20 MB.
If you use Google Drive or Dropbox, selectAdd an accountto connect the service to your Outlook.com account.
Outlook has a limit of 500 recipients per message.
This limit applies to the totality of To, Cc, and Bcc recipients.
The maximum number of people you’re free to add to an Outlook distribution is 60-120.
