Trading was halted around 2 p.m. due to "issues with trading".
In this case, a failure in a central storage appliance linked to both primary and redundant systems prevented failover procedures from engaging, TMX said in its statement.
"This incident was not the result of a cybersecurity attack".
The company says it began fixing the problem Friday afternoon by replacing the defective module and verifying the integrity of the affected data.
The operator said later Friday that all trading would be suspended for the rest of Friday as crews were unable to solve the outage.
TMX Group Ltd, which operates the main Toronto Stock Exchange and smaller trading platforms around Canada, said in a series of Tweets that all users had been "equally impacted and are unable to connect to our exchanges" and it chose to shut down markets for the remainder of the day.
Because of the timing of the failure Friday, TMX Group stated there wasn't time to ensure an orderly market re-open and closing that day.
TMX Group Ltd, which operates the Toronto Stock Exchange and smaller Canadian trading platforms, said it had fixed the error. By 3:30 p.m., TMX tweeted that trading will not resume.
"TMX is committed to applying the lessons learned from this incident to help us prevent such issues from recurring in the future".
"TMX has made a decision to shut down all markets for the remainder of the day". The five-largest stocks traded in the Toronto Stock Exchange are the Royal Bank of Canada, Toronto-Dominion Bank, Bank of Nova Scotia, Suncor Energy and Canadian National Railway. TMX Group is headquartered in Toronto and operates offices across North America (Montréal, Calgary, Vancouver and New York), as well as in key global markets including London, Beijing and Singapore.