macOS Tahoe 26 Developer Beta 5
Apple today provided developers with the fifth beta of macOS Tahoe 26 for testing purposes, with the update coming two weeks after the fourth beta.
There are no updates to the release notes, which still say Beta 4.
THIS IS THE NEW MACINTOSH HD ICON?! WTF
Previously:
Update (2025-08-06): The release notes now say “beta 5” and call out a few changes (integrated into the list, so you have to search for them):
In beta 5 SDK, CoreData changed several
Sendable
annotations to resolve compatibility issues with Swift 6’s newMainActor
default isolation feature. These changes include markingNSManagedObject
asNS_SWIFT_NONISOLATED NS_SWIFT_NONSENDABLE
, markingNSManagedObjectContext
asNS_SWIFT_NONISOLATED NS_SWIFT_SENDABLE
, and requiringNS_SWIFT_SENDABLE
closures for the family ofperform
,performBlock
,performBlockAndWait
and similar methods. These changes are ABI compatible with past releases but might introduce new warnings while building source code that violates the longstanding CoreData concurrency guidelines.
NSManagedObject
are mutable reference types inextricably related to others in a graph and cannot be madeSendable
. They are expected to be isolated to the scope of theNSManagedObjectContext
that creates or fetches them.NSManagedObjectContext
is a style of actor which encapsulates its own dispatch queue. While it’s impermissible to use many methods onNSManagedObjectContext
from other threads, it is permissible to pass references around to invoke theperformBlock
family of methods, for the purpose of routing aSendable
closure to its managed dispatch queue. CoreData supports a user default-com.apple.CoreData.ConcurrencyDebug 1
which can be used to enable additional assertions.
I assume this debugging default still breaks NSAsynchronousFetchRequest
(FB8438285).
Apple has been updating some classic Mac icons during the macOS Tahoe beta, upsetting some longtime Mac users who prefer the original look.
RIP Macintosh HD icon (2001-2025) 🪦💐
An external SSD enclosure that resembles a Samsung T7 but with offset port and vent holes like a Mophie power bank. It makes more sense than a naked hard drive because people always need external storage for their Macs that ship with almost none and can’t house any internal drives anyway. Bold move to put the Apple logo on it though.
Making it look like an SSD is fine, but why make it look like an external SSD? Anyway, the main problem is that it isn’t drawn well. The perspective looks wrong and is very off-putting. They did the same thing with the new icon for mounted disk images.
I want to put a finer point on the problem with this icon: it is not a mere aesthetic preference or a reaction to change, but a simple acknowledgement that this icon is not good. It has a generic quality, a lack of personality. The perspective does not make sense, either. It is just a sad grey box without any connection to literal data storage on a modern Mac, the “Macintosh HD” label beside it on the Desktop, or any object in the real world.
macOS Icon History
Preview
these small things that makes the beta 5 (already) feels half baked. the basic controls have broken layout.
They’ve glassed up the video play button in Safari.
I real curious to see what Apple pro apps like Logic and Final Cut do with Liquid Glass.
i continue to believe that OS 26 is being designed by people that hate computers and don’t understand the people use them.
Previously: