Error: E5BN:E5BN:BIEF and Error: 296J:8B6S:HUCA

[overwatcheddude]

OS: Linux / 6.0.5-arch1-1
App: 1.6.15 / flatpak-1

Neofetch:

OS: Arch Linux x86_64
Kernel: 6.0.5-arch1-1
Uptime: 25 mins
Packages: 659 (pacman), 16 (flatpak)
Shell: bash 5.1.16
Resolution: 1920x1080, 1600x900
DE: Plasma 5.26.2
WM: KWin
Theme: [Plasma], Breeze [GTK2/3]
Icons: [Plasma], breeze-dark [GTK2/3]
Terminal: konsole
CPU: Intel i7-6700K (8) @ 4.300GHz
GPU: NVIDIA GeForce GTX 1080
Memory: 2833MiB / 15934MiB

This error shows up when attempting to unlock a vault. I tried both FUSE and WebDAV, but neither of them worked.

FUSE:

Error Code E5BN:E5BN:BIEF
org.cryptomator.common.vaults.Volume$VolumeException: Unable to mount Filesystem
	at org.cryptomator.desktop@1.6.15/org.cryptomator.common.vaults.FuseVolume.mount(FuseVolume.java:55)
	at org.cryptomator.desktop@1.6.15/org.cryptomator.common.vaults.FuseVolume.mount(FuseVolume.java:42)
	at org.cryptomator.desktop@1.6.15/org.cryptomator.common.vaults.Vault.unlock(Vault.java:155)
	at org.cryptomator.desktop@1.6.15/org.cryptomator.ui.keyloading.KeyLoadingStrategy.use(KeyLoadingStrategy.java:79)
	at org.cryptomator.desktop@1.6.15/org.cryptomator.ui.unlock.UnlockWorkflow.attemptUnlock(UnlockWorkflow.java:72)
	at org.cryptomator.desktop@1.6.15/org.cryptomator.ui.unlock.UnlockWorkflow.call(UnlockWorkflow.java:62)
	at org.cryptomator.desktop@1.6.15/org.cryptomator.ui.unlock.UnlockWorkflow.call(UnlockWorkflow.java:35)
	at javafx.graphics@18.0.2/javafx.concurrent.Task$TaskCallable.call(Task.java:1426)
	at java.base/java.util.concurrent.FutureTask.run(Unknown Source)
	at java.base/java.util.concurrent.CompletableFuture$AsyncRun.run(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.base/java.lang.Thread.run(Unknown Source)
Caused by: org.cryptomator.frontend.fuse.mount.FuseMountException: ru.serce.jnrfuse.FuseException: Unable to mount FS
	at org.cryptomator.frontend.fuse@1.3.4/org.cryptomator.frontend.fuse.mount.AbstractMounter.mount(AbstractMounter.java:46)
	at org.cryptomator.frontend.fuse@1.3.4/org.cryptomator.frontend.fuse.mount.Mounter.mount(Mounter.java:15)
	at org.cryptomator.desktop@1.6.15/org.cryptomator.common.vaults.FuseVolume.mount(FuseVolume.java:53)
	... 12 more
Caused by: ru.serce.jnrfuse.FuseException: Unable to mount FS
	at ru.serce.jnrfuse.AbstractFuseFS.mount(AbstractFuseFS.java:293)
	at org.cryptomator.frontend.fuse@1.3.4/org.cryptomator.frontend.fuse.mount.AbstractMounter.lambda$mount$0(AbstractMounter.java:26)
	... 1 more
Caused by: ru.serce.jnrfuse.FuseException: Unable to mount FS, return code = 1
	at ru.serce.jnrfuse.AbstractFuseFS.mount(AbstractFuseFS.java:289)
	... 2 more

WebDAV:

Error Code 296J:8B6S:HUCA
org.cryptomator.common.vaults.Volume$VolumeException: org.cryptomator.frontend.webdav.mount.Mounter$UnsupportedSystemException: No applicable mounting strategy found for this system.
	at org.cryptomator.desktop@1.6.15/org.cryptomator.common.vaults.WebDavVolume.mountServlet(WebDavVolume.java:86)
	at org.cryptomator.desktop@1.6.15/org.cryptomator.common.vaults.WebDavVolume.mount(WebDavVolume.java:48)
	at org.cryptomator.desktop@1.6.15/org.cryptomator.common.vaults.Vault.unlock(Vault.java:155)
	at org.cryptomator.desktop@1.6.15/org.cryptomator.ui.keyloading.KeyLoadingStrategy.use(KeyLoadingStrategy.java:79)
	at org.cryptomator.desktop@1.6.15/org.cryptomator.ui.unlock.UnlockWorkflow.attemptUnlock(UnlockWorkflow.java:72)
	at org.cryptomator.desktop@1.6.15/org.cryptomator.ui.unlock.UnlockWorkflow.call(UnlockWorkflow.java:62)
	at org.cryptomator.desktop@1.6.15/org.cryptomator.ui.unlock.UnlockWorkflow.call(UnlockWorkflow.java:35)
	at javafx.graphics@18.0.2/javafx.concurrent.Task$TaskCallable.call(Task.java:1426)
	at java.base/java.util.concurrent.FutureTask.run(Unknown Source)
	at java.base/java.util.concurrent.CompletableFuture$AsyncRun.run(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.base/java.lang.Thread.run(Unknown Source)
Caused by: org.cryptomator.frontend.webdav.mount.Mounter$UnsupportedSystemException: No applicable mounting strategy found for this system.
	at org.cryptomator.frontend.webdav@1.2.8/org.cryptomator.frontend.webdav.mount.FallbackMounter.mount(FallbackMounter.java:15)
	at org.cryptomator.frontend.webdav@1.2.8/org.cryptomator.frontend.webdav.servlet.WebDavServletController.mount(WebDavServletController.java:102)
	at org.cryptomator.desktop@1.6.15/org.cryptomator.common.vaults.WebDavVolume.mountServlet(WebDavVolume.java:84)
	... 12 more

[overwatcheddude]

The issue has been resolved after installing fuse2:
pacman -S fuse2

[SailReal]

Thank you for reporting the bug. With what you found out I was able to reproduce it. If fuse2 is not on the system, Cryptomator cannot mount the vault. On Ubuntu I wasn't able to reproduce it, because Flatpak installs Fuse2 as a dependency. Arch, on the other hand, installs Fuse3, Cryptomator currently requires Fuse2 so the problem occurs on Arch, but not on Ubuntu.

We need to check why this declared fuse dependy in Flatpak doesn't work:

org.cryptomator.Cryptomator/org.cryptomator.Cryptomator.yaml

Lines 26 to 37 in 1ec15d8

	modules:
	- name: libfuse
	config-opts:
	- MOUNT_FUSE_PATH=/app/bin
	post-install:
	- install fusermount-wrapper.sh /app/bin/fusermount
	sources:
	- type: archive
	url: https://github.com/libfuse/libfuse/releases/download/fuse-2.9.9/fuse-2.9.9.tar.gz
	sha256: d0e69d5d608cc22ff4843791ad097f554dd32540ddc9bed7638cc6fea7c1b4b5
	- type: file
	path: build-aux/fusermount-wrapper.sh

[SailReal]

Got it, in line 31 we overwrite the fusermount command in the flatpak package with the following wrapper script placed in build-aux/fusermount-wrapper.sh

org.cryptomator.Cryptomator/build-aux/fusermount-wrapper.sh

Line 15 in 1ec15d8

exec flatpak-spawn --host --forward-fd=1 --forward-fd=2 $FD_ARGS fusermount "$@"

exec flatpak-spawn --host ... fusermount ... means we are calling fusermount on the host system which in return means, that a user needs to install Fuse2 when using Cryptomator and what explains why it work on your system after installing Fuse2.

Tried to remove the --host in the wrapper script and not overwrite fusermount but actually call the command in the flatpack package environment but without success. The runtime then complains about missing kernel modules which is probably why this wrapper exists in the first place to call the host system.

The problem now is that Cryptomator does not check if Fuse is installed at all and if so in which version which is quite irritating especially with a packet format which is supposed to do exactly that, encapsulate runtime dependencies.

Will create an issue in the Cryptomator repo to address this. The workaround is and remains exactly your described, install Fuse2 (later Fuse3), but a user should know in any case what to do.

Edit: Here it is: cryptomator/cryptomator#2539