We finally have a preview of the Apple Intelligence features with iOS 18.1 and macOS 15.1 beta, which were released to developers yesterday. As we dig into what’s new in the betas, some Mac users have noticed that it may not be possible to use Apple Intelligence when macOS beta is installed on an external drive.

No AI when running macOS 15.1 beta on an external drive

According to reports, users who tried to enable Apple Intelligence on a macOS installation running on an external drive were unable to experience the feature. Although the option to enable Apple Intelligence is there, the system fails to finish downloading and installing the required language models.

9to5Mac then found an alert message in the beta version of Xcode that explicitly says that the Code Prediction feature “is not available when booting from an external disk.” Based on system logs seen by 9to5Mac, it seems that this restriction applies to all Apple Intelligence features.

It’s unclear at this point whether this is a temporary limitation or whether Apple will in fact not allow users to enable Apple Intelligence when macOS is installed on an external drive. Of course, that’s a huge drawback for beta testers, as many people choose to install the beta system on an external drive rather than update their Mac’s internal drive.

Perhaps Apple has decided to limit AI capabilities to the internal drive to ensure user privacy – but that’s just a theory.

More on Apple Intelligence

Apple Intelligence is what the company is calling its new AI-based features. For example, users can now ask the system to rephrase a text, summarize messages or emails, generate images and even emoji. Siri has also been updated with AI, so that it now understands the context of what’s on the screen and lets users control more aspects of the device.

iOS 18.1 beta and macOS 15.1 beta with Apple Intelligence preview are only available for iPhones, iPads, and Macs compatible with Apple Intelligence. This includes:

If you have an older device (or a non-Pro iPhone 15), you won’t get the latest betas for now.

Apple says that these updates will become available to the public later this year.