Police forces across Canada are warning the public about phone scammers claiming to be Microsoft tech support who are bilking unsuspecting people out of hundreds or even thousands of dollars.

It appears to be the latest version of a four-year-old scam in which people received calls from “Microsoft” or “windows” tech support workers telling them their computer would crash if they didn’t hand over control of the computer to “tech support.”

Once the scammers have “fixed” the problem, they charge the computer owner as much as hundreds of dollars.

According to the Canadian Anti-Fraud Centre, the scam is now so common that it accounts for 70 per cent of the complaints made to the bureau.

The scam has recently been seen in North Bay and Lambton, Ontario, and in the British Columbia interior, but is by no means limited to Canada.

Microsoft issued a warning about it last summer, noting that the scam appears to be targeting English-speaking countries including Canada, Ireland, the U.K. and the U.S.

The Seattle-based software company ran its own survey to determine the scam’s extent, and found 15 per cent of respondents in the targeted areas had received a call of this sort. Some three per cent of those contacted fell for the scam.

The amounts of money bilked from computer users ranged greatly, from an average of $82 in Ireland to an average of $1,562 in Canada.

Numerous YouTube users have posted videos claiming to be recordings of the scam.

Noting the scammers’ accents, many have speculated the ruse originates in India.

Microsoft has asked its customers to beware of unsolicited phone calls related to a security problem, and to never hand over personal information to unsolicited callers.