Some owners of M4 MacBook Airs and M4 Max/M3 Ultra Mac Studios report being unable to update their machines to the macOS 15.4 Release Candidate that was released on Monday. Several users have complained of the issue on on Reddit.
Multiple users report that any attempt to download and install the macOS 15.4 release candidate is met with an error message that reads as follows: “macOS could not be downloaded. Make sure you’re connected to the internet and try again, or contact Apple support for assistance.”
The issue appears to be due to Apple failing to provide the proper decryption key for the M4 MacBook Air and Mac Studio models to install the update. Apple software updates are encrypted, requiring a server-side decryption key for installation. The key for the new Macs is currently not available from Apple’s software server.
Unfortunately, users affected by the issue will not be able to update to the macOS Sequoia 15.4 release candidate until Apple fixes the issue.
Users withe new MacBook Air and Mac Studio models that were previously running macOS 15.4 beta 4 will be able to install the release candidate.
