At a event hosted by Box.com Tim Cook lined up a pretty hefty broadside at Windows 10.
This was somewhat at odds with the main theme of his conversation, which spoke of Apple's improved relationship with Microsoft and how the two companies were better when they worked together.
Cook claimed that trying to build one operating system to work across mobile and desktop was futile and would inevitably lead to a worse user experience.
Bang go any hopes of an iPad Pro running OS X then.
Cook probably isn't talking through his hat here. Microsoft has clearly struggled to translate Windows 10 to mobile thus far. Failed builds and releases, plus what promises to be an incomplete launch feature set don't speak to a seamless user experience from day one.
Unlike the desktop build where Microsoft has been able to address its lack of features and sometimes unstable software by iterating through releases and updates very quickly, the mobile process promises to be less helpful. Carriers and OEMs are going to need to get involved on the process too, unless Microsoft can manage to get agreement to deliver in an iOS-like one hit release.
Potentially that means users losing features on day one and waiting an awful long time to get them back.
For all the promise that Windows 10 Mobile has, I think that Cook has exposed its true weakness and the soft underbelly of Microsoft's strategy going forward. I suspect that this is because, from an Apple point of view, a Microsoft that delivers software and services to run on other platforms is a much better prospect than one that is trying to be more Apple-like.