Malwarebytes v5.2.8.173 component package 128.0.5184 released.   From Malwarebytes 5.0:   Features and improvements Trusted Advisor enhancements: Recommendations are now grouped based on severity Added two new recommendations related to Windows settings note: recommended actions may differ from one device to another based on unique configurations Improved localization support Restricted Allow List rules for Websites to accept domain-only URLs Issues fixed Resolved an issue where Malwarebytes failed to start in some cases when Windows Fast Startup was enabled Additional notes   We have introduced a new versioning system for our component package updates

It's been a long time since I used VBox, as I've switched to Virtual-Machine-Manager (VMM).  But I did have this setup in VBox, once upon a time, with a Linux Host and Windows Guest.   Based on your screenshot, the error provided suggests your permissions in Kubuntu aren't allowing write access to the shared folder.  The link you posted is a strange way to setup the guest in VBox, with CLI rather than GUI, but appears to be correct.  I've used GUI and CLI in the past and the GUI is easier, although CLI is universal for ALL users.  So let's assume you did everything right.   Place a document in your Windows HOST shared folder from within that HOST.  I'll suggest calling the document something like Test-Win2Lin (Test document Windows to Linux) so it can be differentiated from the reverse scenario that failed.  With that document created in the HOST folder, open your GUEST and navigate to the shared folder from within your file manager.  If your document is there, the share is setup correctly and you have a permission problem.  If the document is NOT there, you have a share problem.   Assuming a permission problem, from within your GUEST file manager, navigate to the shared document folder.  Based on your post, it appears to be Scotts_LinuxS_Shared.  Right click on that folder and choose properties, then select the permissions tab.  It should look something like this: I think your error is because you don't have read/write permissions (modify) in Owner or Group.  If I'm correct, use the pull down bar and select "view and modify" for write permission to the shared drive, and click OK.  If your permissions are correct, we've got something else going on (perhaps special characters in your shared folder....the underscores....it's been awhile for me to say for certain.)  Hoping a current VBox user will chime in.  But first things first....you definitely have a permission issue and fixing that may fix everything.   With the correct permissions applied, create a second document in your GUEST and save it to your shared directory.  I'll suggest that document be named Test-Lin2Win (test document Linux to Windows).  You should now have 2 documents in your GUEST shared directory; one shared from Windows to Linux, and one shared from Linux to Windows, and you'll be able to tell which one is which.  Switch over to your HOST and verify you have both documents in the HOST shared directory.  If so, you are good to go.  If not, we'll have to retrace your steps and see where the error occurred.   This is absolutely do-able and at a quick glance, you seem to have done everything correctly.  I'm sure it's something simple & stupid that you'll shake your head and say "awww mannnn!"  Good luck and tell us how you make out!

Many thanks for the reply.   Windows is the Host.   Having set up the shared folder using Virtualbox's Shared Folder menu I was trying to link the Kubuntu (Guest) Desktop Folder to the one on my Windows desktop following an article I found   https://www.geeksforgeeks.org/create-shared-folder-host-os-guest-os-virtual-box/    

Which is the host, Linux or Windows? Why are you using the command line instead of the Vbox sharing? /Devices/Shared folder?

Yeah my bad. Guess I am just a tad grumpy at the moment and venting at big corp. I knew abut xda it is a neat site. 🤓