diff --git a/go.mod b/go.mod
index 0dba770b4..6ae45cc85 100644
--- a/go.mod
+++ b/go.mod
@@ -46,7 +46,7 @@ require (
 	github.com/hashicorp/golang-lru v0.5.4 // indirect
 	github.com/hashicorp/hcl/v2 v2.11.1
 	github.com/hashicorp/nomad/api v0.0.0-20200814140818-42de70466a9d
-	github.com/hashicorp/vagrant-plugin-sdk v0.0.0-20220707165921-a8b5817e43f5
+	github.com/hashicorp/vagrant-plugin-sdk v0.0.0-20220708181224-89ddccf33610
 	github.com/hashicorp/yamux v0.0.0-20200609203250-aecfd211c9ce // indirect
 	github.com/imdario/mergo v0.3.11
 	github.com/improbable-eng/grpc-web v0.13.0
diff --git a/go.sum b/go.sum
index 5d3f00f01..e6d35139b 100644
--- a/go.sum
+++ b/go.sum
@@ -361,10 +361,8 @@ github.com/hashicorp/hcl/v2 v2.11.1 h1:yTyWcXcm9XB0TEkyU/JCRU6rYy4K+mgLtzn2wlrJb
 github.com/hashicorp/hcl/v2 v2.11.1/go.mod h1:FwWsfWEjyV/CMj8s/gqAuiviY72rJ1/oayI9WftqcKg=
 github.com/hashicorp/nomad/api v0.0.0-20200814140818-42de70466a9d h1:afuZ/KNbxwUgjEzq2NXO2bRKZgsIJQgFxgIRGETF0/A=
 github.com/hashicorp/nomad/api v0.0.0-20200814140818-42de70466a9d/go.mod h1:DCi2k47yuUDzf2qWAK8E1RVmWgz/lc0jZQeEnICTxmY=
-github.com/hashicorp/vagrant-plugin-sdk v0.0.0-20220701171937-4cbbeaea0e70 h1:Pqn/v5JGkP20UNz8gyq/bm4OBdhitEqxs5y/+CmaeFY=
-github.com/hashicorp/vagrant-plugin-sdk v0.0.0-20220701171937-4cbbeaea0e70/go.mod h1:bdjvCJEaP+EFbg9vKdYuT5WuCfnFbemm0FEn4KtZaqU=
-github.com/hashicorp/vagrant-plugin-sdk v0.0.0-20220707165921-a8b5817e43f5 h1:ik4/++5TqY2LCBrSAiJHMKV+FGb1ZhnrdD00kyZRejg=
-github.com/hashicorp/vagrant-plugin-sdk v0.0.0-20220707165921-a8b5817e43f5/go.mod h1:bdjvCJEaP+EFbg9vKdYuT5WuCfnFbemm0FEn4KtZaqU=
+github.com/hashicorp/vagrant-plugin-sdk v0.0.0-20220708181224-89ddccf33610 h1:LGVRHdDzPPrHzQ7YjwOXO09+x71WmWjABLwMBepbu6A=
+github.com/hashicorp/vagrant-plugin-sdk v0.0.0-20220708181224-89ddccf33610/go.mod h1:bdjvCJEaP+EFbg9vKdYuT5WuCfnFbemm0FEn4KtZaqU=
 github.com/hashicorp/yamux v0.0.0-20180604194846-3520598351bb/go.mod h1:+NfK9FKeTrX5uv1uIXGdwYDTeHna2qgaIlx54MXqjAM=
 github.com/hashicorp/yamux v0.0.0-20200609203250-aecfd211c9ce h1:7UnVY3T/ZnHUrfviiAgIUjg2PXxsQfs5bphsG8F7Keo=
 github.com/hashicorp/yamux v0.0.0-20200609203250-aecfd211c9ce/go.mod h1:+NfK9FKeTrX5uv1uIXGdwYDTeHna2qgaIlx54MXqjAM=
diff --git a/internal/core/box.go b/internal/core/box.go
index 28c133ef8..18c6fac36 100644
--- a/internal/core/box.go
+++ b/internal/core/box.go
@@ -173,6 +173,9 @@ func (b *Box) loadMetadata() (metadata *BoxMetadata, err error) {
 }
 
 func (b *Box) matches(box core.Box) (bool, error) {
+	if box == nil {
+		return false, nil
+	}
 	name, err := box.Name()
 	if err != nil {
 		return false, err
diff --git a/internal/core/machine.go b/internal/core/machine.go
index 1c8fd9e52..2087b4e4b 100644
--- a/internal/core/machine.go
+++ b/internal/core/machine.go
@@ -71,6 +71,10 @@ func (m *Machine) Box() (b core.Box, err error) {
 
 			return nil, err
 		}
+		if boxName == nil {
+			m.logger.Debug("vagrantfile has no box, so returning nil")
+			return nil, nil
+		}
 		provider, err := m.ProviderName()
 		if err != nil {
 			return nil, err
diff --git a/lib/vagrant/machine/remote.rb b/lib/vagrant/machine/remote.rb
index 430ebe0c8..181092e5c 100644
--- a/lib/vagrant/machine/remote.rb
+++ b/lib/vagrant/machine/remote.rb
@@ -64,6 +64,10 @@ module Vagrant
       # @return [Box]
       def box
         box = client.box
+        # The box itself can be nil in some cases (e.g. for the docker provider)
+        if box.nil?
+          return nil
+        end
         # If the version isn't set, then the box has not being tracked
         # by Vagrant.
         if box.version.empty?
@@ -295,10 +299,13 @@ module Vagrant
         synced_folder_clients = client.synced_folders
         synced_folder_clients.each do |f|
           next if f[:folder][:disabled]
+          # :type will be populated when the Vagrantfile has an explicit type
+          # coming from the user and empty otherwise. when it is empty we can
+          # infer the type from the name of the plugin we get back
           if f[:folder][:type].to_s != ""
             impl = f[:folder][:type].to_sym
           else
-            impl = :virtualbox
+            impl = f[:plugin].name.to_sym
           end
           sf = Vagrant::Plugin::Remote::SyncedFolder.new(client: f[:plugin])
           folder_opts = scoped_hash_override(f[:folder], impl)
diff --git a/lib/vagrant/protobufs/proto/vagrant_plugin_sdk/plugin_pb.rb b/lib/vagrant/protobufs/proto/vagrant_plugin_sdk/plugin_pb.rb
index 8b9e87bb7..81508d24a 100644
--- a/lib/vagrant/protobufs/proto/vagrant_plugin_sdk/plugin_pb.rb
+++ b/lib/vagrant/protobufs/proto/vagrant_plugin_sdk/plugin_pb.rb
@@ -697,6 +697,9 @@ Google::Protobuf::DescriptorPool.generated_pool.build do
     end
     add_message "hashicorp.vagrant.sdk.Target.Machine" do
     end
+    add_message "hashicorp.vagrant.sdk.Target.Machine.BoxResponse" do
+      proto3_optional :box, :message, 1, "hashicorp.vagrant.sdk.Args.Box"
+    end
     add_message "hashicorp.vagrant.sdk.Target.Machine.SetIDRequest" do
       optional :id, :string, 1
     end
@@ -1185,6 +1188,7 @@ module Hashicorp
       Target::GetUUIDResponse = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("hashicorp.vagrant.sdk.Target.GetUUIDResponse").msgclass
       Target::SetUUIDRequest = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("hashicorp.vagrant.sdk.Target.SetUUIDRequest").msgclass
       Target::Machine = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("hashicorp.vagrant.sdk.Target.Machine").msgclass
+      Target::Machine::BoxResponse = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("hashicorp.vagrant.sdk.Target.Machine.BoxResponse").msgclass
       Target::Machine::SetIDRequest = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("hashicorp.vagrant.sdk.Target.Machine.SetIDRequest").msgclass
       Target::Machine::GetIDResponse = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("hashicorp.vagrant.sdk.Target.Machine.GetIDResponse").msgclass
       Target::Machine::SetStateRequest = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("hashicorp.vagrant.sdk.Target.Machine.SetStateRequest").msgclass
diff --git a/lib/vagrant/protobufs/proto/vagrant_plugin_sdk/plugin_services_pb.rb b/lib/vagrant/protobufs/proto/vagrant_plugin_sdk/plugin_services_pb.rb
index 79d0b4ee9..9c45815f3 100644
--- a/lib/vagrant/protobufs/proto/vagrant_plugin_sdk/plugin_services_pb.rb
+++ b/lib/vagrant/protobufs/proto/vagrant_plugin_sdk/plugin_services_pb.rb
@@ -441,7 +441,7 @@ module Hashicorp
           rpc :GetID, ::Google::Protobuf::Empty, ::Hashicorp::Vagrant::Sdk::Target::Machine::GetIDResponse
           rpc :SetState, ::Hashicorp::Vagrant::Sdk::Target::Machine::SetStateRequest, ::Google::Protobuf::Empty
           rpc :GetState, ::Google::Protobuf::Empty, ::Hashicorp::Vagrant::Sdk::Args::Target::Machine::State
-          rpc :Box, ::Google::Protobuf::Empty, ::Hashicorp::Vagrant::Sdk::Args::Box
+          rpc :Box, ::Google::Protobuf::Empty, ::Hashicorp::Vagrant::Sdk::Target::Machine::BoxResponse
           rpc :Guest, ::Google::Protobuf::Empty, ::Hashicorp::Vagrant::Sdk::Args::Guest
           rpc :ConnectionInfo, ::Google::Protobuf::Empty, ::Hashicorp::Vagrant::Sdk::Args::Hash
           rpc :UID, ::Google::Protobuf::Empty, ::Hashicorp::Vagrant::Sdk::Target::Machine::UIDResponse
diff --git a/plugins/commands/serve/client/target/machine.rb b/plugins/commands/serve/client/target/machine.rb
index e44c643a1..b28d5f911 100644
--- a/plugins/commands/serve/client/target/machine.rb
+++ b/plugins/commands/serve/client/target/machine.rb
@@ -14,7 +14,10 @@ module VagrantPlugins
           # @return [Vagrant::Box] box backing machine
           def box
             b = client.box(Empty.new)
-            box_client = Box.load(b, broker: broker)
+            if b == nil || b.box == nil
+              return nil
+            end
+            box_client = Box.load(b.box, broker: broker)
             box = Vagrant::Box.new(
               box_client.name,
               box_client.provider.to_sym,
diff --git a/test/unit/vagrant/machine/remote_test.rb b/test/unit/vagrant/machine/remote_test.rb
index 0f1e3f408..a471b121e 100644
--- a/test/unit/vagrant/machine/remote_test.rb
+++ b/test/unit/vagrant/machine/remote_test.rb
@@ -114,7 +114,7 @@ describe Vagrant::Machine::Remote do
     it "returns a hash with synced_folders returned from the client" do
       synced_folder_clients = [
         {
-          plugin: double("plugin"),
+          plugin: double("plugin", name: "syncedfoldertype"),
           folder: {
             disabled: false,
             source: "/some/source",
@@ -127,7 +127,7 @@ describe Vagrant::Machine::Remote do
       output = subject.synced_folders
 
       expect(output).to match(
-        virtualbox: a_hash_including(
+        syncedfoldertype: a_hash_including(
           "/some/destination" => a_hash_including(
             disabled: false,
             guestpath: "/some/destination",
@@ -141,7 +141,7 @@ describe Vagrant::Machine::Remote do
     it "works with multiple folders for a given impl" do
       synced_folder_clients = [
         {
-          plugin: double("pluginone"),
+          plugin: double("pluginone", name: "syncedfoldertype"),
           folder: {
             disabled: false,
             source: "/one",
@@ -149,7 +149,7 @@ describe Vagrant::Machine::Remote do
           }
         },
         {
-          plugin: double("plugintwo"),
+          plugin: double("plugintwo", name: "syncedfoldertype"),
           folder: {
             disabled: false,
             source: "/two",
@@ -162,7 +162,7 @@ describe Vagrant::Machine::Remote do
       output = subject.synced_folders
 
       expect(output).to match(
-        virtualbox: a_hash_including(
+        syncedfoldertype: a_hash_including(
           "/first" => a_hash_including(
             disabled: false,
             guestpath: "/first",
@@ -190,7 +190,7 @@ describe Vagrant::Machine::Remote do
           }
         },
         {
-          plugin: double("plugintwo"),
+          plugin: double("plugintwo", name: "syncedfoldertype"),
           folder: {
             disabled: false,
             source: "/yesme",
@@ -203,7 +203,7 @@ describe Vagrant::Machine::Remote do
       output = subject.synced_folders
 
       expect(output).to match(
-        virtualbox: a_hash_including(
+        syncedfoldertype: a_hash_including(
           "/pickme" => a_hash_including(
             disabled: false,
             guestpath: "/pickme",
@@ -212,7 +212,7 @@ describe Vagrant::Machine::Remote do
           ),
         )
       )
-      expect(output[:virtualbox]).to_not have_key("/noway")
+      expect(output[:syncedfoldertype]).to_not have_key("/noway")
     end
 
     it "honors explicitly set folder type" do
@@ -227,7 +227,7 @@ describe Vagrant::Machine::Remote do
           }
         },
         {
-          plugin: double("plugintwo"),
+          plugin: double("plugintwo", name: "syncedfoldertype"),
           folder: {
             disabled: false,
             source: "/imnormal",
@@ -240,7 +240,7 @@ describe Vagrant::Machine::Remote do
       output = subject.synced_folders
 
       expect(output).to match(
-        virtualbox: a_hash_including(
+        syncedfoldertype: a_hash_including(
           "/iamdefaulttype" => a_hash_including(
             disabled: false,
             guestpath: "/iamdefaulttype",
@@ -257,7 +257,6 @@ describe Vagrant::Machine::Remote do
           ),
         )
       )
-      expect(output[:virtualbox]).to_not have_key("/noway")
     end
   end
 end