Why the computer freezes when I efile?
Most computers today have firewall software or anti-virus software installed to prevent virus or hacker attack. myTaxExpress EFILE goes through Internet. You need to find a way to add myTaxExpress software as allowed application in firewall or anti-virus software to connect through Internet.
If it's urgent issue, you can also still use CRA EFILE website to submit efile manually. The link is
http://www.efile.cra.gc.ca