I'm using virtualbox 5.2.22.R08 on asustor NAS( last release of OS : 3.4.3.RAE2 ) . Virtual Machine is working fine, but I cannot currently mount vboxsf : I get 'protocol error' message.
Virtual Machine is fedora 30 server, with last update. Current kernel version is 5.3.7-200.fc30.x86_64. Using Vbox guest addition : VBoxGuestAdditions_5.2.35-134035.iso
Former configuration before fedora upgrade was running well since last month : it was Fedora 30 server with 5.3.5-200.fc30.x86_64, and VBoxGuestAdditions_5.2.33-133741.iso
.... ok. after powering off VM ( in order to create vbox.log tar file to join to this topic ) , and not only restarting it, Vboxsf is now working.
Well , I'll leave my intervention here, just in case it might be useful to someone.
