You can configure Mailtrack so that it doesn't track by default every email you send.
To do so:
1) Go to the Account and Settings section in your Mailtrack dashboard.
2) Click Settings and uncheck the Track emails by default option.
3) Click Save changes.
You can also disable the tracking on a per email basis.To do so:
1) Click on the tracking button in the Gmail compose window.
2) Deselect the option Enable tracking for this email.
3) Send the email.