About once a decade, Tim Sweeney, the graphics guru and CEO of Epic Games, stirs the hornet’s nest. He did so on Friday by blasting Microsoft for allegedly trying to close off the Windows 10 store and hurting the much-cherished openness of the personal computer.

In an op-ed piece in the Guardian and in an interview with GamesBeat yesterday, Sweeney said that he worries that Microsoft is making it hard for developers to create games and programs that do not use its Windows app store — a move that could close off what to date has been an open platform.

The future of the Windows PC is at stake here. Sweeney said that the personal computer industry is expected to be open. “Many businesses and the U.S. economy depend on it,” he said. Indeed, the Windows PC has been a platform for economic success, open applications, and third-party developer freedom for a long time. To close it off could be controversial, and that’s why Sweeney is speaking up.

Sweeney said he would be happy to be called a “paranoid conspiracy theorist.” Microsoft has created a Universal Windows Platform (UWP) with Windows 10. It has launched new PC Windows features exclusively in UWP and is “effectively telling developers you can use these Windows features only if you submit to the control of our locked-down UWP ecosystem,” Sweeney wrote.

In response to Sweeney’s allegation, Kevin Gallo, the corporate vice president of Windows at Microsoft, said in a statement to the Guardian, “The Universal Windows Platform is a fully open ecosystem, available to every developer, that can be supported by any store. We continue to make improvements for developers; for example, in the Windows 10 November update, we enabled people to easily side-load apps by default, with no UX required.

“We want to make Windows the best development platform regardless of technologies used and offer tools to help developers with existing code bases of HTML/JavaScript, .NET and Win32, C+ +, and Objective-C bring their code to Windows and integrate UWP capabilities. With Xamarin, UWP developers can not only reach all Windows 10 devices, but they can now use a large percentage of their C# code to deliver a fully native mobile app experiences for iOS and Android. We also posted a blog on our development tools recently.”

But Sweeney wants to know the details. Sweeney said he would love for Microsoft to prove him wrong. But he wants to verify the Windows company’s official position on the details, and he thinks CEO Satya Nadella should speak on the matter and settle it.

Here’s an edited transcript of our interview.

Image Credit: Dean Takahashi

GamesBeat: I wondered how you originally got on the track that [the platform] would be closed since they tend to put this forward as something that’s good for the industry in general. It’s hard to immediately see the part where they’re closing instead of opening.

Tim Sweeney: That’s the area where everyone has to be vigilant. If you look at Windows 10, the design of the operating system encroaches on user freedom more than any past version. Updates continue to push further with the lock screen ads, the extreme difficulty but possibility, technically, of changing your default browser or video player and other things.

My concern is, if you extrapolate that spirit of how Microsoft is running the platform to their strategy with applications, then it looks like it’ll be very easy for them to do to Win32 apps in the future what they’re doing to Chrome and Mozilla today. Making it very inconvenient to do anything outside of Microsoft’s ecosystem. While Microsoft isn’t closing down Windows today, they’re taking steps that appear to go in that direction on many different fronts.

GamesBeat: Were there any obvious places where Epic tools were going to be blocked in the future because of this UWP?

Sweeney: No, not at all. Microsoft has always been a very good partner on the engine side. They use the Unreal engine for many internal projects, including Fable and Gears of War. They’ve always been very supportive. We’ve contributed code back to them. There’s an immense number of people at Microsoft who we’ve had good relationships with. It pains me to criticize this particular aspect of the company, but as company that large has to dealt with one piece at a time.

GamesBeat: You’d like to see them reverse course on this strategy, then? Might that be too hard to do at this point?

Sweeney: Yes, absolutely. I think Windows Store is a great idea. Having a storefront in front of every user in Windows is awesome. The idea of UWP is a great idea. It brings a common set of APIs to all Microsoft devices – PC, console, mobile, and augmented reality. There are lots of good components to this.

What’s required is a very clear commitment from Microsoft that on PC, UWP will remain open. If they made that kind of commitment, everybody in the industry will be able to rely on it as a future evolutionary path to move away from Win32 to UWP and receive the benefits of that, without the fear that Microsoft is going to assert itself between every developer and publisher and their customers as the new commerce monopoly on Windows.

GamesBeat: This is not your job description, but can you explain UWP? I think a lot of people out there are wondering what the jargon means and why it’s important.

Sweeney: Certainly. It’s complicated techie stuff. It’s hard to bring it out of programmer land and into a mainstream understanding. But essentially there are two sets of programming interfaces in Windows which all applications are written to. The existing one is called Win32. Everything from Steam to League of Legends to Photoshop is written to this Win32 interface. And now Microsoft has introduced a new interface that could in the future replace that, called UWP – Universal Windows Platform.

Unlike Win32, UWP has the advantage of supporting a lot of different Microsoft devices besides PCs. It has some advantages and disadvantages, but we can expect Microsoft to improve it over time.

Image Credit: Jordan Novet / VentureBeat

GamesBeat: We had this concern arise in the past on Windows 8. Gabe Newell talked at a GDC about their concern that Microsoft was going to lock down to one store. That would have affected Valve’s Steam store, certainly. He complained at the time, and for some reason or other, that didn’t happen. So it looks like this fear has been around for some time.

Sweeney: Yes. This concern started with Windows 8, and Gabe was the first to speak up about it. But the truth is, the Windows 8 store was such a failure that it made no impact on the industry. There’s no fear that Microsoft will suddenly turn off the switch on all other app stores. The risk is that over time they’ll continue to advantage theirs and disadvantage others, so in the future they can eventually get away with pulling that switch.

What’s happening now with Windows 10, they have a Windows Store with a lot more apps in it, and they’ve just got done launching some major triple-A PC games, like Tomb Raider and Gears of War.

GamesBeat: They’re putting a free version of Forza in there, too.

Sweeney: Right. That’s a good idea. This is an awesome way to launch a store – put out some great products and some free stuff and draw users to it. There’s absolutely nothing controversial about that. My concern is just that by having this new app format that only works practically with the Windows Store, this may be a long-term strategy to disadvantage everybody else.

My fear is stoked somewhat by the Windows 10 experience overall. It’s very hard to replace your default web browser. When you installed Chrome in the past and ran it, it would say, “Want to make Chrome your default web browser?” Now you can’t do that. Microsoft does not allow that. To make Chrome your default web browser, you have to dig through the massive Windows 10 interface, find a hidden scroll bar, and scroll over and click an obscure icon to change it to Chrome.

It’s this spirit of making the system theoretically open – it’s theoretically possible to change your web browser – but so damn difficult that you can expect very few people will do it. So they gain market share for these products unfairly by disadvantaging competitors. It’s very difficult for users to express their personal choice.

GamesBeat: I know they got into trouble with the Justice Department and anti-competitive behavior for actively trying to close off other options in the past. Do you see this in the same way? Whatever they say, [is there] something different about the intention or the viability of the option they have provided?

Sweeney: Let me think about how to answer this carefully. Certainly I don’t think what Microsoft is doing is fair. It’s not clear to me that what Microsoft is doing with many aspects of Windows 10 is legal. It would certainly not be in compliance with the antitrust settlement that Microsoft entered into, the 10-year agreement to refrain from doing a certain set of things, such as what they did to disadvantage Netscape. That period has lapsed and now they’re doing those things again. You can see that clearly in the Windows 10 user interface decisions.

UWP is in the early days. It’s unclear how that particular thing will fall out. But it makes everyone – users, developers, everyone else – question Microsoft’s intentions with this whole thing. It sure doesn’t look good from a user’s point of view.

GamesBeat: You’ve already seen their response to what you wrote in the Guardian. Do you have any sort of reaction to their comment?

Sweeney: Kevin Gallo at Microsoft is a really good guy. I’ve met with him. He said that UWP is in fact open and will support third-party app stores.

GamesBeat: He brought up sideloading, and you brought up sideloading as well.

Sweeney: Yes. That needs more scrutiny. Right after Windows 10 came out, I tried to build a UWP app and distribute it and install it from the web as an experiment. I found a lot of roadblocks. For example, having to create a Microsoft developer account and get Microsoft’s permission to develop for their platform. You have to submit your application to Microsoft and be digitally signed with their DRM.

If you did those things and you changed some operating system settings, which Kevin now says don’t need to be changed, then you could place your application on a web page as a zip file which a user could download and copy into Windows Explorer and dig into to find a script file, which they can run with Windows PowerShell, which has the effect of installing the application. It’s a very complicated process that requires permissions.

In my understanding – and please do seek Kevin’s technical clarification on that process and whether I am wrong – it certainly isn’t at all in the spirit of building and distributing a Win32 app, which anyone can do without Microsoft’s permission. You can have a single button in your web page that downloads it. Click on the download and installs. You’re two mouse-clicks away from any executable program on Windows or Mac, which is the existing status quo. As I’d say, I’d welcome Kevin’s corrections, but this is my experience.

GamesBeat: Have you heard from any other companies in the industry today about what you wrote? Valve in particular.

Sweeney: No, I’m just out there expressing my opinion. It’s all over the web now. But I’m not trying to form some industry coalition. I just want everyone to be able to think about their future software decisions, and Microsoft can think about their software decisions, with full awareness of the future of this thing.

GamesBeat: We should point out that you haven’t been afraid to speak your mind in the past. You have influenced Microsoft’s game consoles – putting more memory into the Xbox 360, for instance, and influencing the design of the original Xbox. This seems like the first time you’ve spoken up in this way, though.

Sweeney: It seems like about once every decade there’s a controversy that Epic takes a public position on. Which is uncomfortable given our role in the industry. But there are forces in play now that everybody needs to know about and understand and think about so that the industry can determine its future with full awareness and not be surprised, five years from now, that it’s been made very difficult to install Win32 apps and Windows Store has gained 90 percent market share. I don’t want that to happen without anyone noticing.

GamesBeat: If we extrapolate this to larger decisions that platform owners make — Apple has almost always historically taken a position that it’s not an open platform. They can make any decisions that they want about how open or closed they want to make their platform. People aren’t used to them being open. Google tends to go the other direction. Other platform companies have a lot of sway in gaming, like Amazon. What do you think about this in that larger context of the other companies out there?

Sweeney: It’s a funny continuum. On one end, there are game consoles, which have always been closed. Their economic model and consumer model is based on that fact. We’ve all accepted that as okay. On the other end you have personal computer operating systems – Windows, Mac, and Linux – which have always been more open, and which everyone expects to be open in the future. Many businesses, and the U.S. economy in general, are in many ways counting on them being open.

Then there are some funny things in between. Nobody complained about iOS being a closed ecosystem when the platform first launched and support for apps was new. Now, with a billion users, Apple has the opportunity to reconsider whether it ought to be the sole gatekeeper of applications on the platform. That’s a valid thing to re-evaluate in light of the scale of the platform.

Image Credit: Valve

GamesBeat: It’s a bit more painful when an open platform moves toward being closed.

Sweeney: Exactly. Everyone’s built up enormous libraries of software and expectations – consumers, developers, and publishers. An enormous industry relies on that platform continuing to be open. We need to be vigilant about any attempts to close it down.

GamesBeat: Valve tried to go a different route with the Steam Machines. It’s not clear that that’s making much of an impact on the market yet. What do you think of that direction?

Sweeney: It’s hard to launch any new operating system in a market that’s already full of many successful operating system and hundreds of millions of devices. If you look at the past decade, the only new operating systems that have launched successfully have been on new types of devices that didn’t exist previously – smartphones and tablets, and now VR and AR.

There’s great difficulty in making Linux into a consumer-friendly operating system, and even more difficulty in garnering the sort of success that Windows and Mac have. When everyone has an existing software library that they’ve invested in for a decade or more, it’s hard to switch to a platform that doesn’t run that.

GamesBeat: It’s a very interesting topic. I hope to see a resolution in the coming days, or however long it takes. Do you have an expectation for when you’ll get some clarity on this?

Sweeney: I’d say the ball is very much in Microsoft’s court. It would be very easy for Microsoft to solve this problem, if Satya Nadella or Bill Gates got up and said, “We’re committed to making UWP an open platform that any company can distribute, any user can install from the web, as easily as any existing application. The entire software ecosystem can count on this.” The industry would say, “Great. Problem solved.”

In Windows 10 right now, with UWP not behaving that way—These might just be some temporary limitations. But Microsoft has been very silent. That silence needs to be broken with very clear statements. Not just platitudes about UWP being open, but commitments and details.

GamesBeat: Do you have anything else you’d like to add?

Sweeney: No, I don’t think so. But I’d certainly invite commentary and rebuttal from Microsoft. The problems we’re expressing are with something that’s completely reversible. All they need to do is say ain’t so and do so with sufficient clarity that the industry can count on it. I’ll be very happy to be proven a paranoid conspiracy theorist.