macOS Tahoe - does not detect external disk and ext4 volumes on the disk.

[samuelyounge]

Describe the bug

macOS Tahoe - does not detect external disk and ext4 volumes on the disk.
I verified that the the extension is active in Settings extensions section. It should and when opening ExtendFS it show green and claims it is active.

I tried using "diskutil list" also but, external disk and volumes on it do not show.

I just paid $15 bucks for ExtendFS but, it does pretty much nothing.

Steps to reproduce

1. Install the ExtendFS app from Apple App Store
2. Start the app
3. Open Settings Preferences as directed by app
4. Ensure it is enabled and active
5. Plug in external USB SSD Disk
6. Look for in Finder (not there)
7. Look for using "diskutil list" (not there)
8. Open Disk Utility and look for disk (not there)

Expected results

External disk and ext4 partitions show in Finder and Terminal "diskutil list"
Able to mount in Disk Utility

Actual results

Nothing

Screenshots

No response

macOS version

macOS Tahoe v26.5.1

ExtendFS version

1.2.0 (21)

Logs and crash reports

No response

Additional context

No response

[kthchew]

First, some clarifying questions:

Look for using "diskutil list" (not there)

Do you mean that there are no entries at all that correspond to the plugged in USB device?

Typically, you should see some whole disk (e.g. something of the form /dev/disk4 (external, physical)), and underneath it its partition table (e.g GUID_partition_scheme) and a list of its partitions (e.g. of the form disk4s1, disk4s2, ...). Do you see anything like that?

/dev/disk4 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *8.1 GB     disk4
   1:                        EFI EFI                     209.7 MB   disk4s1
   2:           Linux Filesystem                         7.7 GB     disk4s2

Note that something like the above should be appearing in diskutil list output regardless of whether ExtendFS is installed or not. (Typically, a default install of macOS can identify a "Linux Filesystem" in diskutil list but can't mount it.) The main difference if ExtendFS is installed is that the name of the volume may appear in that output. If none of that output is appearing, it likely indicates that macOS itself isn't able to access the USB's volumes properly for whatever reason (and is probably the reason ExtendFS isn't working, as the system needs to see the volumes first before it can send them to ExtendFS for reading).

Open Disk Utility and look for disk (not there)

As with before, can you clarify whether "not there" means that, in the Disk Utility sidebar

1. You can see the physical disk, but not its partitions; or
2. You can't see any entries at all corresponding to the physical USB disk

(Please make sure View > Show All Devices is selected first)

---

For a first step, I'd try restarting the Mac. I've seen some issues from time to time related to FSKit/mounting that a reboot has resolved in the past.

If, after a restart, things still don't work, I'll need some additional information as well:

1. Follow these steps and paste the output of the logs here:
   a. Enable ExtendFS
   b. Reboot the machine
   c. After the machine has started up again, plug in your USB drive
   d. Open Terminal
   e. Paste this command: sudo log show --last 5m --predicate "(subsystem in { 'com.apple.FSKit', 'com.apple.LiveFS', 'com.kpchew.ExtendFS.ext4Extension' }) || (process in { 'diskarbitrationd', 'fskitd', 'fskit_agent' })"
   f. Copy and paste the output of that command here (if it's very long, you might want to upload it to a pastebin website and put the link here, which works as well).
2. If you know, how was the ext4 partition created (e.g. using gparted, something else)?
3. Is the partition scheme on the USB drive MBR or GPT?