Account administrators can change these settings by logging in to CONTROL PANEL and navigating to the Services > Mailboxes page.
Note: By default, these settings are set to maximum for each user on the account.
- Incoming and outgoing message size (MB)
- Recipients per message (number allowed per message)
- Mailbox size
- Other limitations
- Allowing the settings to be modified by individual users from the My Services interface
Mailboxes are set up by default with the maximum message size limit of 51200 KB (50 MB) for both sending and receiving messages. This limit can be decreased.
Note: for Exchange 2016, the following limitation are currently hard-coded and cannot be modified:
- OWA – 35MB
- EWS – 35MB
- ActiveSync – 20MB
Note: Mailbox-specific limits are not respected by EWS mail clients, such as Entourage EWS, Outlook 2011 or Apple Mail Exchange account. For listed clients default limit of 50 MB will be applied regardless of the settings in CONTROL PANEL.
Notes about message size limits:
- The message size limit for the emails sent from mobile devices is 20 MB in total and ~16.6 MB for attachments. Due to the routing the size of a message increases by about 20% which means that the original size of a message sent from a mobile device should be less than 16 MB.
- Due to message encoding that is used to transfer the message through the Internet, the size of the message can grow substantially. The "encoded message size" is the size of the resulting email message with all of the attachments added and encoded using MIME. This encoded size is the actual size of the message as it travels over the Internet and is always larger than the raw size because of the MIME overhead and because binary attachments are generally encoded using base64 encoding. Base64-encoded files are usually about 137% the size of the original files. Additionally, the encoded message contains all of the metadata about the message — and this information grows as the message travels from the sender to the recipient.
Warning: If you send a very large message, it stays in the Outbox until the file is uploaded to the server. This can block other messages. Please keep this in mind when setting the message size limits.
The maximum number of recipients per message depends on the plan selected for your account. By default this setting is set to maximum for each user on the account. You may set this limit to a lower number.
Note: On Exchange, if the message is sent to a distribution list created on your Smarsh Hosted Services Exchange account, the distribution list is viewed as one (1) recipient regardless of the number of members in the list. If the contact group (sometimes called local distribution list) is created in OWA, the number or recipients is equal to the number of members.
By default mailbox size is not limited.
The size limitation is set for the whole account storage which depends on your plan.
To check the current usage and add additional storage, navigate to Services > Mailboxes > Disk Qouta Management.
However, we do not recommend to maintain large mailboxes as it can lead to poor Outlook performance.
While the overall size of .ost files has a preconfigured limit of 50 gigabytes (GB), Microsoft recommends to avoid the Outlook data files growing larger than 10 GB. Read the Microsoft KB article on the connection between Outlook data file size and Outlook behavior for more information.
You can control the size of individual mailboxes by establishing send and receive limits for the mailboxes in your account. Read the Knowledge Base article on How To Use Storage Management On Exchange Account for more information.
- Company Contacts (total number allowed)
- Distribution lists (total number allowed)
- Inbound domains (total number allowed)
- Maximum attachment size per email (KB)
- Top-level public folders (total number allowed)
- Maximum public folder item size (MB)
You can refer to CONTROL PANEL > Account > Plan & Pricing Information page for details.
Note: if you're using an SMTP application to send messages via an authenticated relay, there is a limitation of 50 messages per minute per connector.
To change the limit for an individual mailbox, click the display name of the mailbox you would like to change settings for, then click Advanced Settings.
- Navigate to Users > User Permissions
- To edit permissions for multiple users, navigate to Users > User Permissions and click the Default Permissions button.
- To edit permissions for one user, click the user's display name, then click the Set user permissions link