Hi everyone, I'm trying to implement my own virtual disk using a custom File System extension. As a starting point, I used this sample: https://github.com/KhaosT/FSKitSample. I can successfully build and run the app. I also enabled the custom File System extension under System Settings → General → Login Items & Extensions. However, I'm not sure how to proceed from there. My goal is to mount the virtual disk so that it appears directly in Finder. Currently, I am only able to mount it manually using Terminal commands, as shown in the sample: hdiutil attach -imagekey diskimage-class=CRawDiskImage -nomount dummy # (this returns e.g. disk35) mkdir /tmp/TestVol mount -F -t MyFS disk35 /tmp/TestVol While this technically mounts the volume, it does not show up in Finder, and I don't know how to make it visible there. Could anyone please point me in the right direction? What is the correct approach to have the mounted volume appear in Finder automatically? Thanks in advance!

Thanks for the response! I'm currently using the plain mount command because I need to explicitly specify my custom file system (e.g., using -t myfs), which diskutil mount doesn’t support — it assumes known file system types and doesn’t allow passing a custom FS type parameter. If I try diskutil mount /dev/disk36, it responds with “Volume(s) mounted successfully”, but as expected, the volume doesn't show up in Finder. In Disk Utility, the disk appears as “Apple read/write Media - Uninitialized”, and if I attempt to format it, my custom FSKit-based file system is not listed as an available format. Additionally, if I try to format the disk manually using: diskutil eraseDisk MyFS Test /dev/disk36 I get the error: MyFS does not appear to be a valid file system format So currently, I'm relying on mounting the FS manually via Terminal, and everything works at the file system level — but I’m still looking for a way to expose it properly to Finder as a recognized and accessible volume. Any insight into how to achieve that — possibly by integrating with Disk Arbitration or notifying the system in another way — would be greatly appreciated.