Outlook times-out when I try to send emails larger than 1 MB. However, I am able to receive mail of any size and have no problems sending small messages. How can I send bigger files?

Most internet connections have an asymmetric speed, meaning that the download speed is much faster than the upload speed. This means that you may have no difficulty downloading large messages, because they come down a relatively fast download link. However, if you try to send an email with a large attachment it can take much longer because the upload link is slower. If the file is large enough, and the upload link is relatively slow, the send operation can time-out because Outlook thinks it is taking too long to send the email and assumes the mail server has timed-out (i.e. is no longer responding). This can be fixed by increasing the mail server timeout value in Outlook. Go to the “Tools” menu > “Account Settings”. In the Account Settings window that appears, click the “E-Mail” tab. This will list all the email accounts on your computer. Select your email account and click the “Change” button. Within the Change E-Mail Account window, click the “More Settings” button in the bottom right-hand corner. In the next window that appears, click the “Advanced” tab. You should see a slider labelled “Server Timeouts”. Increase this slider to 5 minutes. Click OK to save and close the windows. Once back at the Outlook window try sending an email to see whether the increased timeout fixes the problem. If not, try increasing the timeout even more (to a maximum of 10 minutes).

Should the problem continue the next most common cause is antivirus software. It has been reported that some antivirus programs which scan outbound email messages can cause the sending process to be slowed (or even temporarily suspended) making it seem like the email server is timing-out, when the problem is actually a lack of communication from the computer itself to the email server. To test this theory, disable any scanning of outbound email messages in your antivirus package. If this solves the problem then you may need to leave this feature temporarily disabled until you find a proper solution (such as checking whether any updates are available for the software which resolve this issue, or check with the manufacturer as to whether this is a known issue with a fix or workaround). In theory, disabling outbound email scanning should not present a major security risk as your antivirus scanner should detect viruses resident on your computer, so the risk of sending a virus through email is relatively minimal. However, it would be good to get this feature running again for optimal protection.