I had a pretty strange issue recently with how QuickBooks works with Samba. The fix was to disable ACLs for SMB. While this seems like a silly issue for silly software, it’s worth noting the fix. Before doing so, it’s worth mentioning that defaults write /Library/Preferences/SystemConfiguration/com.apple.smb.server AclsEnabled -bool NO If yore having saving issues from QuickBooks and this doesn’t fix your issue I’d immediately switch back: sudo defaults write /Library/Preferences/SystemConfiguration/com.apple.smb.server AclsEnabled -bool YES