MacOS 15.4: 2025 Macs cannot cope with the release candidate

MacOS 15.4's release candidate version that has been available since Monday does not run on Apple's latest computers. Affected participants in the beta test program for developers report this Among other things on Reddit. Accordingly, the installation fails on the MacBook Air M4 as well as on the Mac Studio M3 Ultra and the Mac Studio M4 Max. The three machines were presented in early March.

Confusing error message

According to those affected, the error message appears during the download or at the latest before the installation starts that the update cannot be downloaded. You should check your internet connection or contact Apple's support. The use of the IPSW package for the purpose of a DFU installation also fails. Some beta testers tried three times in a row – no attempt to do so. On the other hand, the release candidate runs without any problems on older Macs up to the last variants of the MacBook Pro (with M4, M4 Pro and M4 Max).

The reason for the difficulties seems to be that Apple apparently failed to provide the necessary keys for the new Macs with which the update packages can be deciphered and then installed. Apple wants to ensure that no malware or incorrect software is installed – the signature is also checked. How Macrumors reportsthe necessary key is currently still missing on Apple's own download server. The error message is accordingly confusing.

Server -side solution is conceivable

At the moment there is no solution for the problem. It is unclear whether Apple can play a simple server -side fix (i.e. provide the key) or put the release candidate from MacOS 15.4 again. Problems with other new devices from the spring of 2025 – iPad 11 and iPad Air M3 – and their software update (iPados 18.4 RC) do not seem to be available, only Macs are affected.

A release candidate version is always one of the last variants of an update before the final version is provided-it is not uncommon for the RC version to be the final version. Among other things, MacOS 15.4 delivers Apple Intelligence in German.