Windows 11 users who have customized the interface of the operating system with a third-party app may run into trouble with the incoming 24H2 update later this year, if what’s happening in testing is anything to go by.

Tom’s Hardware spotted a Neowin report noting that in the recently deployed preview build 26100 of Windows 11, which is supposedly the RTM version of the 24H2 update, Microsoft has stealthily (and rather crudely) disabled some apps that modify the interface.

Specifically, StartAllBack and ExplorerPatcher are the two UI customization apps that are blocked from Windows 11 24H2, meaning you won’t be able to get the update until you remove that software.

So, why has this happened? As you might guess, the reason for effectively casting aside these third-party apps is bound up in the compatibility and possible stability and security issues that they cause, as Windows development MVP Rafael Rivera makes clear on X (formerly Twitter).

There are plenty of reasons to skewer Microsoft, but this isn't one of them. Here, Microsoft is blocking unreliable high crash rate software that is extremely sensitive to OS changes.Fixing the bugs and revving the version number is likely all that's needed here (this time). https://t.co/bm8E8LEdZ4April 6, 2024

Indeed, as Neowin points out, when you attempt to install ExplorerPatcher on build 26100, the OS tells you that it can’t be run because the app “causes security or performance issues on Windows.”

As one bright spark on X observes, tongue firmly planted in cheek, Microsoft Teams is also “an unreliable high crash rate bit of software” so why doesn’t Microsoft block that from installing? Well, Rivera does respond to that little bit of trolling, noting that whatever stability issues Teams may have, it doesn’t prevent OS boot or recovery options – suggesting there are some serious flaws with these customization apps and the 24H2 update.

If you recall, 24H2 has an all-new underlying platform called Germanium, so there are some big changes here – and we’re guessing that this shift under the hood is the reason for the apps being problematic. That’s pure guesswork, mind.

Whatever the reason behind the apparently thorny compatibility issues, there are problems with the way Microsoft has gone about this. Communication with the software developers would be expected – and normally happens in these kinds of cases, at least giving them some warning of what’s going on. Not this time, though.

Furthermore, the way the ban appears to have been implemented seems very crude – it’s a blanket ban on all EXE files containing the names of the offending apps (which means all versions are affected, and any related apps). The way this has been done smacks of either laziness or a rush to get this move through, which isn’t a good look for Microsoft.

It almost seems like Microsoft has jammed this in at a late stage because the 24H2 update RTM needed to be pushed out of the door sharpish. There was a problem found last-minute and a fix was hastily applied using a hatchet, not a scalpel (again, guesswork – but this is what it feels like).

That theory does make some sense, as the predicted date for the RTM (near-finalized) candidate of the 24H2 update was April, and this build needs to be ready for new Snapdragon X Elite AI PCs which are coming in June (in theory). These laptops require that Germanium build due to their ARM-based chips, so there’s a critical need to get this done.

In short, it’s all a bit messy and some feathers have definitely been ruffled here – although due to the mentioned shoddy implementation of the app ban, it’s actually very easy to circumvent it: simply rename the EXE of the client. We wouldn’t recommend doing that, mind – as if the hints about boot failure are on the money, your PC could end up with a serious spanner in the works.

Meanwhile, these customization apps still work with Windows 11 23H2, the current version, and we have to remember that these changes are still in testing. We don’t know if this ban is temporary, or whether it’ll actually be enforced when 24H2 arrives later this year (from September, most likely).

Microsoft and the relevant devs should be able to work together and find a better solution, indeed a full resolution, before then, and Rivera’s comments indicate this will be the case.

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