Microsoft has drawn up a short list of more than 1,000 UK resellers it knows have bought illegal software, and will be contacting each one this year to ensure they become compliant.
The vendor also claimed last week that it has returned at least £20m worth of incremental business to UK channel partners following its piracy purge last year.
Alex Hilton, UK group manager licence compliance at Microsoft, said the vendor has doubled its anti-piracy team and invested "significant resources" in fighting the counterfeiters. "It is not about persecuting VARs but we want to make sure they know to buy through authorised distributors," he said.
"This is about putting revenue back into the channel to create a level playing field for legitimate partners."
Jon Atherton, group vice-president at authorised distributor Enta, said: "We receive a lot of calls from resellers and system builders presented with low-cost products that seem too good to be true.
"Many resellers buy software unwittingly, only to discover they have supplied customers with counterfeit (products) and are exposing both themselves and their customers to much greater problems."
Hilton added: "We admit this can never be erased completely but we are confident we can decrease it considerably." He said Microsoft is looking into a "sub distribution" programme to ensure non-authorised distributors operate a legal channel.
However, Hilton stressed that Microsoft will not be lenient on repeat offenders. "We will work hard on pursuing those that continue to buy illegal software and ensure they are stopped once and for all," he said.
A particular target this year is hard-disk loaders - VARs that install the same piece of software on multiple computers. "We will be particularly stringent with them," Hilton said.
Andy Rutley, commercial director at system builder NS Optimum, said: "The channel is cleaner than it was last year as we don't tend to come up against cut-price sites as much as we used to.
"However, Microsoft could do more by setting up a hotline for customers to call and receive a clear-cut answer from the vendor itself about whether or not it is legitimate to buy from a particular partner."
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