Spain's competition commission said on Tuesday it has opened an anti-trust investigation into Microsoft's Spanish and Irish subsidiaries, on grounds that the company "blocked the sale by third parties" of PC software licences.
Though details at this stage are sketchy, it is thought that the watchdog believes that collected information could indicate a possible violation of Spanish competition regulations.
The investigation and ruling "must be completed within 18 months", the Wall Street Journal's MarketWatch reports.
Microsoft's relationship with Europe has been fraught with difficulties over the past decade.
The European Commission, Europe's upper house, ordered the Redmond-based company to pay $613 million in fines in 2004, after an antitrust settlement over its Windows Media Player software was brought against the company. It also forced Microsoft into creating versions of its popular operating systems and products for European consumers, such as Windows and Windows Media Player.
Microsoft's 'browser ballot' screen for Windows users in Europe
More recently, Microsoft was forced to display a 'browser ballot' screen for Windows users in Europe, allowing users to pick a browser of their choice, to open up competition away from Internet Explorer. Bundling the still popular browser with the operating system had been seen as an 'anti-competitive move' by the company by European regulators.
Earlier this year, Microsoft took an antitrust suit of its own against Google to Europe's upper house, alleging anti-competitive behaviour in Europe's search market. Europe has been investigating Google's search practices in the region, to determine whether it abuses its search position.
Microsoft recently angered the European Parliament, the lower house, after its UK managing director Gordon Frazer, admitted that the company's cloud-based services in Europe and further afield were vulnerable to U.S. inspection and intelligence gathering.
The European Parliament is investigating the reach of the Patriot Act. The Dutch government recently announced that it would ban U.S. providers until the reach of the U.S. counter-terrorism laws could be gauged.