Encontrei o mesmo erro que você:
% sudo kextunload -b com.github.osxfuse.filesystems.osxfusefs
(kernel) Kext com.github.osxfuse.filesystems.osxfusefs not found for unload request.
Failed to unload com.github.osxfuse.filesystems.osxfusefs - (libkern/kext) not found.
Mas eu continuei com o restante das instruções desse link:
# Use new kernel extension:
sudo /bin/cp -RfX \
/usr/local/Cellar/osxfuse/2.6.2/Library/Filesystems/osxfusefs.fs /Library/Filesystems
sudo chmod +s \
/Library/Filesystems/osxfusefs.fs/Support/load_osxfusefs
E agora está funcionando bem. Espero que ajude.