[Galaxy Note 10.1 (2014 Edition) General] BarryH_GEG:
When I was excluding s/w it was because the devices that work and don't work all have the same Samsung-provided s/w. If the ROM is the same and devices using it behave differently doing the exact same thing that's a totally different problem than if EU s/w is fine and the U.S. s/w isn't. If device "A" works fine with app "X" and device "B" is used the exact same way and doesn't, how is that Samsung's fault and, without diving in to how app "X" is written, how is Samsung supposed to identify and correct the issue?

Is this true for everyone? When I tested Chromecast I used Netflix and PlayOn and they worked fine. If everyone reporting a Chromecast problem is able to cast some apps and not others that's a very different and more complex problem.

According to Bubblesoft (the maker of Cast To UPnP/DLNA), the issue is with Samsung's volume thingy. The stock ROM/Touchwiz puts the volume panel into the notification bar and pulling it down causes the error. Since according to this thread it also happens with Chromecast I guess it's Sammy's fault.​

The above can't be true. If it were, the problem would be all or nothing. The fact that some apps have no issue with "Samsung's volume thingy" means the problem most likely lies on the app side.

There are two ways for developers to utilize Chromecast:

Use the imbedded Chromecast media player

"You have many options for displaying content on Chromecast. For simple media applications, you can use the default media player that can play back HTML5 media content. You can also customize it with your own branding and style using CSS. "

Build your own receiver app that lives on the Chromecast device

"You can build your own custom receiver application using standard web technologies. With a custom receiver you can build virtually any application while including support for many streaming protocols, including MPEG-DASH, HLS, and Microsoft Smooth Streaming, all of which are available in the Media Player Library."

http://googledevelopers.blogspot.com/2014/02/ready-to-cast-chromecast-now-open-to.html

So for an app to cast to Chromecast, there's lots of work on the "app owner's" side to make that happen. And how they do it can range from simple (utilize Google's imbedded receiver with no modification) to complex (build their own receiver app and customize their device app to interact with it). The fact some apps work means for those that don't somebody's coded outside the SDK or there's a bug in 4.4 that causes proper SDK/API code to misbehave. Samsung's proprietary code could be borking something but I'm more inclined to go with specific app developers and/or Android code introduced in 4.4 as the problem. The reason being I'd think if it were Samsung's code it would be an all or nothing problem.

As to why now on 4.4 and why other 4.4 devices (even Samsung's) aren't experiencing the issue, good question. All OEMs use different s/w and apps (except Nexus) on their large format tablets. Everyone's using published APIs to code against. Samsung's N10.1-14 code may be using APIs that are problematic in 4.4 that have never been exposed before. Samsung could have coded against an API incorrectly. Chromecast's new and its SDK not familiar to third party developers so they could be creating the problem at the app level.

Regardless, with all that said, until someone (Google, Samsung, app developers) "owns" the problem there won't/can't be a fix.