Microsoft has confirmed that the Windows 10 version 1903 update is blocked for some Mac users.
According to a Microsoft support page discovered by Windows Latest, the update will fail to install on Mac devices from 2012 or earlier as well as new Apple systems with Windows Support drivers installed and those running older versions of Boot Camp, a utility that allows Mac users to switch between macOS and Windows.
More specifically, Macs with MacHALDriver.sys dated September 24, 2011 01:57:09 or older in Windows\system32\drivers are affected.
Users operating on one of these machines will receive an error message when they attempt to update Windows, "Mac HAL Driver - machaldriver.sys: Your PC has a driver or service that isn't ready for this version of Windows 10."
Microsoft doesn't specify why the update won't go through, only that there is a "compatibility hold" on these specific devices. It's also not clear whether this is deliberate or caused by some kind of flaw.
Whatever the case, Microsoft does at least provide some instructions that could help Mac users force the update. The software giant suggests updating Apple Boot Camp and Windows Support Software drivers to the latest versions. You can do so by selecting the Apple menu and checking for an update in the App Store. If that doesn't work, Microsoft says to follow the instructions on this Apple support page for getting Windows Support Software after you've installed Boot Camp.
Microsoft is currently working on a solution to the compatibility problem and excepts to push out a fix by the end of July.
Windows 10 version 1903 introduces a number of features for IT pros, including Autopilot, a group of apps for setting up and pre-configuring devices, as well as security improvements, like auto labeling, which will detect when a file has sensitive information in it.