I recently installed the McAfee internet protection package offered by Cox. Since then, when sending e-mail I often get an error message the first time. Then I try again and the message is sent. I checked Mozilla and found this information.
| Thunderbird All versions and McAfee | High CPU usage, a message 'Sending of message failed. Unable to open the temporary file C:\Users\<user name>\AppData\Local\Temp\nsmail.tmp. Check your 'Temporary Directory' setting.' and in extreme cases Thunderbird crashes | McAfee have been aware of the issue since early 2013. Issues should be raised with McAfee so that they can fix their product. |
Is Cox doing anything to influence a fix with McAfee?