If you have obtained a legitimate large file and need to open it:
Depending on your goal, here are the proper ways to access similar large-scale "million-plus" Canadian data files legally: 1. Official Population & Demographic Data
These provide anonymized records of millions of individuals from the Census.
Access the Government of Canada's Business Registry to find information on over 1.1 million federal corporations. 3. Voter & Contact Lists (Important Legal Note)
Using unauthorized personal data for marketing can result in heavy fines.