UPDATE: ====== I have found this is due to bug(s) in the Rust Coreutils (specifically md5sum), I believe.
General Info on change from GNU CoreUtils to Rust CoreUtils in this article: https://discourse.ubuntu.com/t/ubuntu-25-10-foundations-edition-what-s-coming-and-what-s-next/68147 Info on problems with Rust Coreutils (uutils): https://www.reddit.com/r/linux/comments/1nr1bas/ubuntu_2510s_move_to_rust_coreutils_is_causing/ I was able to fix the issue, by removing the Rust CoreUtils and installing the GNU CoreUtils: sudo apt install --allow-remove-essential coreutils-from-gnu coreutils-from-uutils- Then rebooted the VM, and selected Devices > Insert Guest Additions CD Image, then opened a Terminal at the CD path, then ran: sudo sh ./VBoxLinuxAdditions.run Then to allow access to shared VirtualBox folder: sudo usermod -a -G vboxsf $USER And this installed the VirtualBox Guest Additions just fine! So the Main Bug is with md5sum in Rust CoreUtils (uutils) - see: https://bugs.launchpad.net/ubuntu-release-notes/+bug/2125535 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2123903 Title: Virtualbox Guest Addition update fails in 25.10 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/virtualbox/+bug/2123903/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
