Microsoft has been criticized for various aspects of its products and business practices. Issues with ease of use, robustness, and security of the company's software are common targets for critics. In the 2000s, a number of malware mishaps targeted security flaws in Windows and other products. Microsoft was also accused of locking vendors and consumers in to their products, and of not following or complying with existing standards in its software. Total cost of ownership comparisons between Linux and Microsoft Windows are a continuous point of debate.
The company has been the subject of numerous lawsuits, brought by several governments and by other companies, for unlawful monopolistic practices. It was the subject of the landmark 1998 United States v. Microsoft Corp. American antitrust law case, during which Microsoft CEO Bill Gates was called "evasive and unresponsive" and the company's officials were found on a number of occasions to have falsified evidence. In 2004, the European Union found Microsoft guilty in the Microsoft Corp. v. Commission case, and it received an 899 million euro fine.
Ties to US Government departments On September 14, 2019, Microsoft's flagship store was shut down by protestors as part of a direct action organized by Close the Camps NYC. The action was in response to Microsoft's $19.4 million contract with U.S. Immigration and Customs Enforcement (ICE). Microsoft's relationship with the immigration enforcement agency was revealed by executive Tom Keane, through a company blog post that described ICE's use of the company's high-security cloud storage product Azure Government. He went on to say the company is "proud to support" the work of ICE. As of January 2026, ICE had more than tripled the amount of data stored in Microsoft's Azure platform.
In February 2019, some of Microsoft's employees protested the company's war profiteering from a $480 million contract to develop augmented reality headsets for the United States Army.
Copyright enforcement When Microsoft discovered that its first product, Altair BASIC, was subject to widespread unauthorized copying, Microsoft founder Bill Gates wrote an Open Letter to Hobbyists that openly accused many hobbyists of stealing software. Gates' letter provoked many responses, with some hobbyists objecting to the broad accusation, and others supporting the principle of compensation. This disagreement over whether software should be proprietary continues into the present day under the banner of the free software movement, with Microsoft characterizing free software released under the terms of the GPL as being "potentially viral" and the GNU General Public License itself as a "viral license" which "infects" proprietary software and forces its developer to have to release proprietary source to the public.
The Halloween documents, internal Microsoft memos which were leaked to the open source community beginning in 1998, indicate that some Microsoft employees perceive "open source" software — in particular, Linux — as a growing long-term threat to Microsoft's position in the software industry. The Halloween documents acknowledged that parts of Linux are superior to the versions of Microsoft Windows available at the time, and outlined a strategy of "de-commoditize[ing] protocols & applications." Microsoft stated in its 2006 Annual Report that it was a defendant in at least 35 patent infringement lawsuits. The company's litigation expenses for April 2004 through March 2007 exceed $4.3 billion: over $4 billion in payouts, plus $300 million in legal fees.
Another concern of critics is that Microsoft may be using the distribution of shared source software to harvest names of developers who have been exposed to Microsoft code, as some believe that these developers could someday be the target of lawsuits if they were ever to participate in the development of competing products. This issue is addressed in published papers from several organizations including the American Bar Association and the Open Source Initiative.
Starting in the 1990s, Microsoft was accused of maintaining "hidden" or "secret" APIs: interfaces to its operating system software that it deliberately keeps undocumented to gain a competitive advantage in its application software products. (public comment on US v. Microsoft under the Tunney Act) Microsoft employees have consistently denied this; they claim that application developers inside and outside Microsoft routinely reverse-engineered DOS and 16-bit versions of Windows without any inside help, creating legacy support problems that far exceeded any alleged benefit to Microsoft. In response to court orders, Microsoft has published interfaces between components of its operating system software, including components like Internet Explorer, Active Directory, and Windows Media that sell as part of Windows but compete with application software.
On October 10, 2018, Microsoft joined the Open Invention Network community despite holding more than 60,000 patents.
Mono patent concerns
On July 6, 2009, Microsoft announced that it was placing their ECMA 334 and ECMA 335 specifications under their Community Promise pledging that they would not assert their patents against anyone implementing, distributing, or using alternative implementations of .NET. Mono's implementation of those components of the .NET stack not submitted to the ECMA for standardization has been the source of patent violation concerns for much of the life of the project. In particular, discussion has taken place about whether Microsoft could destroy the Mono project through patent suits.
The base technologies submitted to the ECMA, and therefore also the Unix/GNOME-specific parts, are claimed to be safe due to Microsoft's explicitly placing both ECMA 334 (C#) and ECMA 335 (CLI) standards under the Microsoft Community Promise. The concerns primarily relate to technologies developed by Microsoft on top of the .NET Framework, such as ASP.NET, ADO.NET and Windows Forms (see non-standardized namespaces), i.e. parts composing Mono's Windows compatibility stack. These technologies are today not fully implemented in Mono and not required for developing Mono-applications, they are simply there for developers and users who need full compatibility with the Windows system.
In June 2009 the Ubuntu Technical Board stated that it saw "no reason to exclude Mono or applications based upon it from the archive, or from the default installation set."
The Free Software Foundation's Richard Stallman has stated on June 2, 2009, that "[...] we should discourage people from writing programs in C#. Therefore, we should not include C# implementations in the default installation of GNU/Linux distributions or in their principal ways of installing GNOME". On July 1, 2009, Brett Smith (also from the FSF) stated that "Microsoft's patents are much more dangerous: it's the only major software company that has declared itself the enemy of GNU/Linux and stated its intention to attack our community with patents.", "C# represents a unique threat to us" and "The Community Promise does nothing to change any of this".
Fedora Project Leader Paul Frields has stated, "We do have some serious concerns about Mono and we'll continue to look at it with our legal counsel to see what if any steps are needed on our part", yet "We haven't come to a legal conclusion that is pat enough for us to make the decision to take mono out".
In November 2011 at an Ubuntu Developer Summit, developers voted to have the Mono-based Banshee media player removed from Ubuntu's default installation beginning on Ubuntu 12.04; although reported reasonings included performance issues on ARM architecture, blocking issues on its GTK+ 3 version, and it being, in their opinion, "not well maintained", speculation also surfaced that the decision was also influenced by a desire to remove Mono from the base distribution, as the remaining programs dependent on Mono, gbrainy and Tomboy, were also to be removed. Mono developer Joseph Michael Shields defended the performance of Banshee on ARM, and also the claims that Banshee was not well-maintained as being a "directed personal insult" to one of its major contributors.
Ignoring unauthorized copying
Microsoft ignored unauthorized copying of its own software for their benefit on the long term. While talking about users in China who do not pay for the software they use in 2006, to an audience at the University of Washington, Bill Gates said "And as long as they're going to steal it, we want them to steal ours. They'll get sort of addicted, and then we'll somehow figure out how to collect sometime in the next decade."
The practice allowed Microsoft to gain some dominance over the Chinese market and only then taking measures against unauthorized copies. In 2008, by means of the Windows update mechanism, a verification program called "Windows Genuine Advantage" (WGA) was downloaded and installed. When WGA detects that the copy of Windows is not genuine, it periodically turns the user's screen black. This behavior angered users and generated complaints in China with a lawyer stating that "Microsoft uses its monopoly to bundle its updates with the validation programs and forces its users to verify the genuineness of their software".
Licensing agreements
A common complaint comes from those who want to purchase a computer that usually comes preinstalled with Windows without a copy of Windows pre-installed and without paying extra for the license either so that another operating system can be used or because a license was already acquired elsewhere, such as through the MSDN Academic Alliance program. Microsoft encourages original equipment manufacturers (OEMs) to supply computers with Windows pre-installed by presenting their dominance in computer sales and arguing that consumers benefit by not having to install an operating system. Because the price of the license varies depending on discounts given to the OEM and because there is no similar computer that the OEM offers without Windows, there is no immediate way to find the size of the refund. In 2009, Microsoft stated that it has always charged OEMs about $50 for a Windows license on a $1,000 computer.
While it is possible to obtain a computer with no or free operating systems, virtually all large computer vendors continue to bundle Microsoft Windows with the majority of the personal computers in their ranges. The claimed increase in the price of a computer resulting from the inclusion of a Windows license has been called the "Windows tax" or "Microsoft tax" by opposing computer users. The Findings of Fact in the United States Microsoft antitrust case of 1998 established that "One of the ways Microsoft combats piracy is by advising OEMs that they will be charged a higher price for Windows unless they drastically limit the number of PCs that they sell without an operating system pre-installed. In 1998, all major OEMs agreed to this restriction." Microsoft also once assessed license fees based on the number of computers an OEM sold, regardless of whether a Windows license was included; Microsoft was forced to end this practice due to a consent decree. In 2010, Microsoft stated that its agreements with OEMs to distribute Windows are nonexclusive, and OEMs are free to distribute computers with a different operating system or without any operating system.
Microsoft does not provide refunds for Windows licenses sold through an OEM, including licenses that come with the purchase of a computer or are pre-installed on a computer.