Microsoft has recently increased to 150 MB the maximum size that an attachment and/or an email message can be. However, sending an email message of this size is dependent upon what application you use to send the email, and where the recipient's mailbox resides.
It is generally considered best practice to not send emails with large attachments, but to send a link to that attachment instead as this would quickly fill up your mailbox, it will tie up your mailbox while the file is being sent, and it slows down the servers that are processing the mail.
See https://services.dartmouth.edu/TDClient/KB/ArticleDet?ID=66997 for information on sending a link to a file you have stored in OneDrive.
It is also important to note that this change does not mean that the types of files that are prohibited from being emailed has changed (e.g. files with a .exe extension, etc.). Those file types are prohibited as they are a very common way for people to send computer viruses.
If you do need to send a large email message, below are some guidelines to help you understand what will and will not work.
| Client |
Send Messages Up to 150 MB |
Receive/Open Messages Up to 150 MB |
| Outlook on the Web |
No - link with OneDrive |
Yes |
| Outlook 2016 for Mac |
Yes |
Yes |
| Outlook 2016 for Windows |
Yes |
Yes |
| Apple Mail |
Yes |
Yes |
| Gmail |
No - link with Google Drive |
No |
| Hotmail/Live |
No - link with OneDrive |
No |
See https://technet.microsoft.com/en-us/library/exchange-online-limits.aspx#Anchor_4 for more information on mailbox limits.