Poland’s Office for Competition and Consumer Protection (UOKiK) has complained to the European Commission about Microsoft Windows being on laptops to the exclusion of Linux.

It suspects collusion between Microsoft and the laptop makers that Microsoft allegedly greases with rebates, a charge reminiscent of AMD’s complaints against Intel that the EC is also pursuing.

Poland also suspects the practice is true across the European Union, which is why went to the EC.

It said it forwarded to Brussels the results of its investigation of the terms and conditions under which laptop makers sell the widgets.

According to Polish press reports, “Around a dozen producers had admitted that ‘the bases of cooperation with Microsoft are so attractive that they have practically no choice.’”

The investigation reportedly began in December after the UOKiK received complaints from Polish consumers wanting a choice.

IDC says 96% of the 1.5 million laptops sold in Poland last year had Windows pre-installed.

The EC, which has already nailed Microsoft for a fortune in antitrust fines, is currently investigating its Office monopoly.