diff --git a/lib/vagrant/machine_index.rb b/lib/vagrant/machine_index.rb
index 02fd13db9..29788ebaa 100644
--- a/lib/vagrant/machine_index.rb
+++ b/lib/vagrant/machine_index.rb
@@ -263,7 +263,7 @@ module Vagrant
     #
     # @return [Hash]
     def find_by_prefix(prefix)
-      return if !prefix
+      return if !prefix || prefix == ""
       @machines.each do |uuid, data|
         return data.merge("id" => uuid) if uuid.start_with?(prefix)
       end
diff --git a/test/unit/plugins/commands/destroy/command_test.rb b/test/unit/plugins/commands/destroy/command_test.rb
index 782455d17..73ea9b45d 100644
--- a/test/unit/plugins/commands/destroy/command_test.rb
+++ b/test/unit/plugins/commands/destroy/command_test.rb
@@ -164,11 +164,18 @@ describe VagrantPlugins::CommandDestroy::Command do
       subject.execute
     end
 
-    context "with an invalid argument" do
+    context "with machine that does not exist" do
       let(:argv){ ["notweb"] }
       it "raises an exception" do
         expect { subject.execute }.to raise_error(Vagrant::Errors::MachineNotFound)
       end
     end
+
+    context "with an invalid argument" do
+      let(:argv){ [""] }
+      it "raises an exception" do
+        expect { subject.execute }.to raise_error(Vagrant::Errors::MachineNotFound)
+      end
+    end
   end
 end
diff --git a/test/unit/vagrant/machine_index_test.rb b/test/unit/vagrant/machine_index_test.rb
index 5556063af..09fa755a0 100644
--- a/test/unit/vagrant/machine_index_test.rb
+++ b/test/unit/vagrant/machine_index_test.rb
@@ -108,6 +108,11 @@ describe Vagrant::MachineIndex do
       expect(subject.get(nil)).to be_nil
     end
 
+    it "returns nil if the machine doesn't exist (is an empty string)" do
+      expect(subject.get("")).to be_nil
+      expect(subject.get(nil)).to be_nil
+    end
+
     it "returns a valid entry if the machine exists" do
       result = subject.get("bar")
 
@@ -144,7 +149,6 @@ describe Vagrant::MachineIndex do
       expect(subject.include?(nil)).to be(false)
     end
 
-
     it "locks the entry so subsequent gets fail" do
       result = subject.get("bar")
       expect(result).to_not be_nil