diff --git a/lib/vagrant/errors.rb b/lib/vagrant/errors.rb
index 619803022..5a219570e 100644
--- a/lib/vagrant/errors.rb
+++ b/lib/vagrant/errors.rb
@@ -936,6 +936,10 @@ module Vagrant
       error_key(:virtualbox_disks_controller_not_found)
     end
 
+    class VirtualBoxDisksPrimaryNotFound < VagrantError
+      error_key(:virtualbox_disks_primary_not_found)
+    end
+
     class VirtualBoxGuestPropertyNotFound < VagrantError
       error_key(:virtualbox_guest_property_not_found)
     end
diff --git a/plugins/providers/virtualbox/cap/cleanup_disks.rb b/plugins/providers/virtualbox/cap/cleanup_disks.rb
index c6c0ce466..ec95c604d 100644
--- a/plugins/providers/virtualbox/cap/cleanup_disks.rb
+++ b/plugins/providers/virtualbox/cap/cleanup_disks.rb
@@ -27,12 +27,16 @@ module VagrantPlugins
         # @param [Hash] disk_meta - A hash of all the previously defined disks from the last configure_disk action
         def self.handle_cleanup_disk(machine, defined_disks, disk_meta)
           controller = machine.provider.driver.get_controller('SATA')
-          primary_disk = controller.attachments.detect { |a| a[:port] == "0" && a[:device] == "0" }[:uuid]
+          primary = controller.attachments.detect { |a| a[:port] == "0" && a[:device] == "0" }
+          if primary.nil?
+            raise Vagrant::Errors::VirtualBoxDisksPrimaryNotFound
+          end
+          primary_uuid = primary[:uuid]
 
           if disk_meta
             disk_meta.each do |d|
               dsk = defined_disks.select { |dk| dk.name == d["name"] }
-              if !dsk.empty? || d["uuid"] == primary_disk
+              if !dsk.empty? || d["uuid"] == primary_uuid
                 next
               else
                 LOGGER.warn("Found disk not in Vagrantfile config: '#{d["name"]}'. Removing disk from guest #{machine.name}")
diff --git a/plugins/providers/virtualbox/cap/configure_disks.rb b/plugins/providers/virtualbox/cap/configure_disks.rb
index 14913fac3..2edb557f8 100644
--- a/plugins/providers/virtualbox/cap/configure_disks.rb
+++ b/plugins/providers/virtualbox/cap/configure_disks.rb
@@ -69,6 +69,9 @@ module VagrantPlugins
             # always come in port order, but primary is always Port 0 Device 0.
             controller = machine.provider.driver.get_controller('SATA')
             primary = controller.attachments.detect { |a| a[:port] == "0" && a[:device] == "0" }
+            if primary.nil?
+              raise Vagrant::Errors::VirtualBoxDisksPrimaryNotFound
+            end
             primary_uuid = primary[:uuid]
 
             current_disk = all_disks.select { |d| d["UUID"] == primary_uuid }.first
diff --git a/templates/locales/en.yml b/templates/locales/en.yml
index a553b68e3..a6a27b877 100644
--- a/templates/locales/en.yml
+++ b/templates/locales/en.yml
@@ -1683,6 +1683,10 @@ en:
         '%{storage_bus}', but no such controller was found. Please add the
         proper controller to your guest using provider-specific
         customizations.
+      virtualbox_disks_primary_not_found: |-
+        Vagrant was not able to detect a primary disk attached to the SATA
+        controller. Vagrant Disks requires that the primary disk be attached
+        to the first port of the SATA controller in order to manage it.
       virtualbox_disks_defined_exceed_limit: |-
         VirtualBox only allows up to 30 disks to be attached to a single guest using the SATA Controller,
         including the primray disk.
diff --git a/test/unit/plugins/providers/virtualbox/cap/cleanup_disks_test.rb b/test/unit/plugins/providers/virtualbox/cap/cleanup_disks_test.rb
index a505a1d1b..6eedf57db 100644
--- a/test/unit/plugins/providers/virtualbox/cap/cleanup_disks_test.rb
+++ b/test/unit/plugins/providers/virtualbox/cap/cleanup_disks_test.rb
@@ -63,6 +63,12 @@ describe VagrantPlugins::ProviderVirtualBox::Cap::CleanupDisks do
 
         subject.cleanup_disks(machine, defined_disks, disk_meta_file)
       end
+
+      it "raises an error if primary disk can't be found" do
+        allow(sata_controller).to receive(:attachments).and_return([])
+        expect { subject.cleanup_disks(machine, defined_disks, disk_meta_file) }.
+          to raise_error(Vagrant::Errors::VirtualBoxDisksPrimaryNotFound)
+      end
     end
 
     context "with dvd attached" do
diff --git a/test/unit/plugins/providers/virtualbox/cap/configure_disks_test.rb b/test/unit/plugins/providers/virtualbox/cap/configure_disks_test.rb
index 9cc5fa682..5ae19f423 100644
--- a/test/unit/plugins/providers/virtualbox/cap/configure_disks_test.rb
+++ b/test/unit/plugins/providers/virtualbox/cap/configure_disks_test.rb
@@ -142,6 +142,12 @@ describe VagrantPlugins::ProviderVirtualBox::Cap::ConfigureDisks do
       expect(primary_disk).to eq(all_disks.first)
     end
 
+    it "raises an error if primary disk can't be found" do
+      allow(sata_controller).to receive(:attachments).and_return([])
+      expect { subject.get_current_disk(machine, defined_disks.first, all_disks) }.
+        to raise_error(Vagrant::Errors::VirtualBoxDisksPrimaryNotFound)
+    end
+
     it "finds the disk to configure" do
       disk = subject.get_current_disk(machine, defined_disks[1], all_disks)
       expect(disk).to eq(all_disks[1])