Opening MTP Android device fails with "the location is not a folder" while gvfs mount is healthy

[vinnythefemboy]

Description

Clicking an Android phone (connected via USB in MTP / File Transfer mode) from Nemo's sidebar or "Devices" view produces the error "the location is not a folder". The device's mtp:// URI fails to open as a browsable folder in Nemo, even though the gvfs MTP backend has successfully mounted the device.

Environment

• Linux Mint 22.3 (Cinnamon), Ubuntu 24.04 base
• Nemo: 6.6.3
• gvfs-backends: 1.54.4-0ubuntu1~24.04.2
• gvfs-fuse: 1.54.4-0ubuntu1~24.04.2
• libmtp9t64: 1.1.21-3.1ubuntu1

Device

• Samsung Galaxy phone, Android 16, connected via USB, "File transfer (MTP)" mode selected
• USB ID: 04e8:6860 (Samsung Galaxy series, MTP mode)

Steps to reproduce

1. Connect Android phone via USB.
2. On the phone, select "File transfer / Android Auto" USB mode.
3. In Nemo, click the phone entry in the sidebar (or the "SAMSUNG Android" volume).

Expected behavior

Nemo opens the phone's storage and lists its top-level folders (DCIM, Download, etc.).

Actual behavior

Nemo shows: "the location is not a folder" and does not browse into the device.

Diagnostic evidence the mount is actually healthy

`gio mount -li` reports:
```
Volume(0): SAMSUNG Android
Type: GProxyVolume (GProxyVolumeMonitorMTP)
activation_root=mtp://SAMSUNG_SAMSUNG_Android_/
Mount: mtp -> mtp://SAMSUNG_SAMSUNG_Android_/
```

And the FUSE path is fully browsable:
```
$ ls "/run/user/1000/gvfs/mtp:host=SAMSUNG_SAMSUNG_Android_/"
Internal storage
```

Workaround

Opening the FUSE path directly works:
```
nemo "/run/user/1000/gvfs/mtp:host=/Internal storage"
```

So the gvfs MTP mount itself is fine — the issue appears to be in how Nemo navigates `mtp://` URIs from the sidebar/device entry.

Additional notes

• Not covered by existing issues "Unable To Open MTP Device" when I plug in my phone #2734, MTP error when connecting phone #2663, or Segfault when accessing an Android device right after clicking "accept" on the Android device #3474 (those describe mount failures or segfaults — here the mount succeeds).
• Related but distinct from No image/video preview with MTP connected mobile phone storage (Linux Mint 21.2 - victoria) #3291 (preview with MTP).

[Jeremy7701]

As it happens...
In LMDE7
I've just plugged in my Samsung mobile, selected 'read/write' on the phone.
(It's quite an old model - probably an A10?

I can access the phone and its SD card in nemo via the Desktop icon without any trouble.

ran 'gio mount -li'
(Omitting all information about hard disks or a NFS mount),

Volume(0): SAMSUNG Android
  Type: GProxyVolume (GProxyVolumeMonitorMTP)
  ids:
   unix-device: '/dev/bus/usb/001/008'
  activation_root=mtp://SAMSUNG_SAMSUNG_Android_R58M83EFHJY/
  themed icons:  [multimedia-player]
  symbolic themed icons:  [multimedia-player-symbolic]  [multimedia-symbolic]  [multimedia-player]  [multimedia]
  can_mount=1
  can_eject=0
  should_automount=1
  Mount(0): SAMSUNG Android -> mtp://SAMSUNG_SAMSUNG_Android_R58M83EFHJY/
    Type: GProxyShadowMount (GProxyVolumeMonitorMTP)
    default_location=mtp://SAMSUNG_SAMSUNG_Android_R58M83EFHJY/
    themed icons:  [multimedia-player]
    symbolic themed icons:  [multimedia-player-symbolic]  [multimedia-symbolic]  [multimedia-player]  [multimedia]
    can_unmount=1
    can_eject=0
    is_shadowed=0
Mount(1): mtp -> mtp://SAMSUNG_SAMSUNG_Android_R58M83EFHJY/
  Type: GDaemonMount
  default_location=mtp://SAMSUNG_SAMSUNG_Android_R58M83EFHJY/
  themed icons:  [multimedia-player]  [multimedia]  [multimedia-player-symbolic]  [multimedia-symbolic]
  symbolic themed icons:  [drive-removable-media-symbolic]
  can_unmount=1
  can_eject=0
  is_shadowed=1