By default, the maximum file size of a single attachment that users can send is 3072 KB, and the maximum file size of multiple attachments that BlackBerry® devices can send in a single email message is 5120 KB.

1. In the BlackBerry Administration Service, on the Servers and components menu, expand BlackBerry Solution topology > BlackBerry Domain > Component view > Email.
2. Click the instance that you want to change.
3. Click Edit instance.
4. On the Messaging tab, in the Messaging options section, perform any of the following actions:
   • To change the maximum file size for a single attachment that BlackBerry devices can send, in the Maximum single attachment upload size (KB) field, type a number that is between 1 and 3072 KB.
   • To change the maximum file size of multiple attachments that BlackBerry devices can send at one time, in the Maximum multiple attachment upload size (KB) field, type a number that is between 1 and 5120 KB that is greater than the value in the Maximum single attachment upload size (KB) field.
5. Click Save all.

If you prevent users from sending large attachments, they can only send specific attachments, such as certificates and contact list entries, that are less than a single packet.

1. In the BlackBerry® Administration Service, on the Servers and components menu, expand BlackBerry Solution topology > BlackBerry Domain > Component view > Email.
2. Click the instance that you want to change.
3. Click Edit instance.
4. On the Messaging tab, in the Messaging options section, in the Maximum single attachment upload size (KB) field, type 0.
5. Click Save all.

On BlackBerry® devices that are running specific versions of the BlackBerry® Device Software, users can download attachments in native formats (for example, .txt for a text file) to their BlackBerry devices. Users can open and make changes to the files that they download using an appropriate third-party application on their BlackBerry devices. A user might be able to open specific file formats using the media application on the BlackBerry device.

The default maximum file size of attachments that users can download to their BlackBerry devices is 3072 KB (3 MB).

1. In the BlackBerry Administration Service, on the Servers and components menu, expand BlackBerry Solution topology > BlackBerry Domain > Component view > Email.
2. Click the instance that you want to change.
3. Click Edit instance.
4. On the Messaging tab, in the Messaging options section, in the Maximum single attachment download size (KB) field, type a number, in KB, that is between 0 and 10240 (10 MB). If you type 0, users cannot download attachments in a native format to their BlackBerry devices.
5. Click Save all.