Three big changes coming to macOS virtual machines: USB accessory access, including external storage, guest provisioning, and layered disk images for VMs.

In Ventura, VM disk performance was poor, with write speeds of 0.7 GB/s. How fast is it now in macOS 26.4, and how does using FileVault affect it? Plus a note on problems with BSIs in VMs.

When trouble strikes a disk image, macOS normally refuses to accept and mount it. This details how to use hdiutil to attach the image as a device so it can be repaired by fsck_apfs.

The new ASIF disk image type is now 18 months old. How well does it perform? Is it as good as claimed? It all depends on whether you want to use encryption.

They come in a multitude of formats and variants, and are used throughout macOS and apps. How do you use them, and what should be wary of?