I solved this problem for myself by using the diskutil tool available from the Mac terminal, and also available from an ssh session into the Mac.
The following web page was most helpful to me: https://www.MacObserver.com/tips/deep-dive/resize-your-apfs-container/ I used commands provided by that page as templates to downsize my apfs container, and to create an ExFAT volume that's now directly visible whether I'm booted to my Bootcamp enabled Windows 10 or to High Sierra. hth Janina E.T. writes: > Latest macOS High Sierra. I need to resize two partitions on an external > drive. I can shrink one down but it creates a new partition and I cannot add > that space to the other partition. What do I need to do to make this work? > Thanks. > > From E.T.'s Keyboard... > ancient.ali...@icloud.com > Many believe that we have been visited > in the past. What if it were true? > > -- > The following information is important for all members of the Mac Visionaries > list. > > If you have any questions or concerns about the running of this list, or if > you feel that a member's post is inappropriate, please contact the owners or > moderators directly rather than posting on the list itself. > > Your Mac Visionaries list moderator is Mark Taylor. You can reach mark at: > mk...@ucla.edu and your owner is Cara Quinn - you can reach Cara at > caraqu...@caraquinn.com > > The archives for this list can be searched at: > http://www.mail-archive.com/macvisionaries@googlegroups.com/ > --- You received this message because you are subscribed to the Google > Groups "MacVisionaries" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to macvisionaries+unsubscr...@googlegroups.com. > To post to this group, send email to macvisionaries@googlegroups.com. > Visit this group at https://groups.google.com/group/macvisionaries. > For more options, visit https://groups.google.com/d/optout. -- Janina Sajka Linux Foundation Fellow Executive Chair, Accessibility Workgroup: http://a11y.org The World Wide Web Consortium (W3C), Web Accessibility Initiative (WAI) Chair, Accessible Platform Architectures http://www.w3.org/wai/apa -- The following information is important for all members of the Mac Visionaries list. If you have any questions or concerns about the running of this list, or if you feel that a member's post is inappropriate, please contact the owners or moderators directly rather than posting on the list itself. Your Mac Visionaries list moderator is Mark Taylor. You can reach mark at: mk...@ucla.edu and your owner is Cara Quinn - you can reach Cara at caraqu...@caraquinn.com The archives for this list can be searched at: http://www.mail-archive.com/macvisionaries@googlegroups.com/ --- You received this message because you are subscribed to the Google Groups "MacVisionaries" group. To unsubscribe from this group and stop receiving emails from it, send an email to macvisionaries+unsubscr...@googlegroups.com. To post to this group, send email to macvisionaries@googlegroups.com. Visit this group at https://groups.google.com/group/macvisionaries. For more options, visit https://groups.google.com/d/optout.