Meta pushes Muse past 3.4 million downloads as it embraces the app's open filesystem

Meta puts its weight behind Muse

Meta spent this week's Connect developer conference pushing Muse, the AI app it launched on September 8, announcing a slate of upcoming capabilities including video chat with the Muse avatar, computer-use support on the Mac, a dedicated email address, more partners and connectors, and planned smart-glasses integrations, according to TechCrunch.

The promotional effort is paying off in install numbers, though the estimates vary widely by firm. Sensor Tower put Muse at more than 3.4 million downloads as of its Thursday estimates, up from over 2.5 million at the start of the week. Apptopia counted 4.3 million total downloads, 2.6 million of them on iOS, while Appfigures saw roughly 2.3 million installs split almost evenly between iOS and Android. The app is currently available only in the United States and Canada.

Sensor Tower noted its figures can lag real-world adoption, meaning they may not fully capture the bump from Connect. Even so, the early trajectory stands out. According to Sensor Tower data cited by TechCrunch, Muse reached an estimated 2.8 million downloads in its first two weeks while averaging 55 percent day-over-day download growth between September 8 and 17. By comparison, ChatGPT averaged 24 percent day-over-day download growth in its first 10 days, while download growth for Claude and Grok declined during their respective launches. Muse hit the top of the US App Store on September 18 and has held the spot, and it reached number one on the Google Play Store on September 19. Sensor Tower also found Muse's daily active users climbed 27 percent on Wednesday after Connect wrapped.

The marketing machine behind the numbers

Meta began running house ads for Muse on September 9, a day after launch, and within 10 days Muse had received the majority of house advertising promotions across Meta's properties, ahead of promotions for Facebook, Instagram and WhatsApp, per Sensor Tower. The company has also bought ads on mobile ad networks and on Reddit, TikTok and YouTube, and by Tuesday, September 22, Muse ranked among the top 10 brands by advertising spend.

Still, the growth appears largely organic: TechCrunch reports that ads promoting Muse accounted for only 6 percent of ad impressions from launch through September 19. Meta's Head of Threads, Connor Hayes, told Business Insider that marketing Muse differs from marketing Threads. Rather than matching user-generated content to people's interests, the goal is building promotional units that showcase something the AI agent can do for a specific user, based on Meta's understanding of what would be useful to them.

A filesystem Meta now says is meant to be open

In a separate development, The Verge reported that Muse, which had begun exposing its filesystem to curious users on Wednesday after some prodding, now readily hands over its contents when asked. Muse itself had initially told users, including The Verge, that it was not supposed to reveal those files.

Meta's Nat Friedman later said the behavior was intended, and David Singleton of Meta Superintelligence Labs explained on X that it was a deliberate choice: a user's Muse Secure VM is in effect their own computer in the cloud, where they can install software, write and compile code, and browse the web. Singleton described it as the user's own Linux box to operate as they choose, and said Muse's architecture is fundamentally different from platforms like ChatGPT and Gemini, closer to running OpenClaw on a local machine except the machine sits in the cloud.

The experience has changed noticeably between the two days. On Wednesday, Muse offered only a text file download showing its directory tree and refused a full archive of the root directory, saying it could not do a full copy even with secrets stripped out. On Thursday, it presented a clickable file browser with access to root and zipped up the root directory without hesitation, delivering full filesystem listings with secrets removed. Meta spokesperson Daniel Roberts told The Verge the company is continuing to update the product, so users may see changes in how much information is available about their virtual machine. Meta has not responded to The Verge's question about why Muse initially treated filesystem access as a security issue if it was always intended.

Why it matters

Muse's early numbers, driven more by organic interest than by paid placement, suggest Meta may have the first credible challenger to ChatGPT's mainstream momentum, and its cross-app distribution gives it a runway rivals lack. Equally significant is the filesystem episode: Muse appears to be an agent running on a personal cloud VM whose internals users can inspect, a very different design from closed chatbot platforms. That inspectability is unusual and, as the initial exposure of details users were never meant to see showed, potentially revealing. The fact that Muse refused access one day and packaged the whole root directory the next also highlights a persistent problem for AI agents: they are often unreliable judges of their own permissions, and Meta has yet to explain which version of the behavior was actually the plan.