diff --git a/builder/vmware/builder.go b/builder/vmware/builder.go
index 49196da89..fb8933d1a 100644
--- a/builder/vmware/builder.go
+++ b/builder/vmware/builder.go
@@ -1,6 +1,7 @@
 package vmware
 
 import (
+	"fmt"
 	"github.com/mitchellh/mapstructure"
 	"github.com/mitchellh/multistep"
 	"github.com/mitchellh/packer/packer"
@@ -50,10 +51,11 @@ func (b *Builder) Prepare(raw interface{}) (err error) {
 		b.config.OutputDir = "vmware"
 	}
 
+	errors := make([]error, 0)
 	if b.config.RawBootWait != "" {
 		b.config.BootWait, err = time.ParseDuration(b.config.RawBootWait)
 		if err != nil {
-			return
+			errors = append(errors, fmt.Errorf("Failed parsing boot_wait: %s", err))
 		}
 	}
 
@@ -63,12 +65,16 @@ func (b *Builder) Prepare(raw interface{}) (err error) {
 
 	b.config.SSHWaitTimeout, err = time.ParseDuration(b.config.RawSSHWaitTimeout)
 	if err != nil {
-		return
+		errors = append(errors, fmt.Errorf("Failed parsing ssh_wait_timeout: %s", err))
 	}
 
 	b.driver, err = b.newDriver()
 	if err != nil {
-		return
+		errors = append(errors, fmt.Errorf("Failed creating VMware driver: %s", err))
+	}
+
+	if len(errors) > 0 {
+		return &packer.MultiError{errors}
 	}
 
 	return nil
diff --git a/builder/vmware/builder_test.go b/builder/vmware/builder_test.go
new file mode 100644
index 000000000..052c15d8f
--- /dev/null
+++ b/builder/vmware/builder_test.go
@@ -0,0 +1,83 @@
+package vmware
+
+import (
+	"github.com/mitchellh/packer/packer"
+	"testing"
+	"time"
+)
+
+func testConfig() map[string]interface{} {
+	return map[string]interface{}{
+	}
+}
+
+func TestBuilder_ImplementsBuilder(t *testing.T) {
+	var raw interface{}
+	raw = &Builder{}
+	if _, ok := raw.(packer.Builder); !ok {
+		t.Error("Builder must implement builder.")
+	}
+}
+
+func TestBuilderPrepare_BootWait(t *testing.T) {
+	var b Builder
+	config := testConfig()
+
+	// Test with a bad boot_wait
+	config["boot_wait"] = "this is not good"
+	err := b.Prepare(config)
+	if err == nil {
+		t.Fatal("should have error")
+	}
+
+	// Test with a good one
+	config["boot_wait"] = "5s"
+	err = b.Prepare(config)
+	if err != nil {
+		t.Fatalf("should not have error: %s", err)
+	}
+}
+
+func TestBuilderPrepare_Defaults(t *testing.T) {
+	var b Builder
+	config := testConfig()
+	err := b.Prepare(config)
+	if err != nil {
+		t.Fatalf("should not have error: %s", err)
+	}
+
+	if b.config.DiskName != "disk" {
+		t.Errorf("bad disk name: %s", b.config.DiskName)
+	}
+
+	if b.config.OutputDir != "vmware" {
+		t.Errorf("bad output dir: %s", b.config.OutputDir)
+	}
+
+	if b.config.SSHWaitTimeout != (20 * time.Minute) {
+		t.Errorf("bad wait timeout: %s", b.config.SSHWaitTimeout)
+	}
+
+	if b.config.VMName != "packer" {
+		t.Errorf("bad vm name: %s", b.config.VMName)
+	}
+}
+
+func TestBuilderPrepare_SSHWaitTimeout(t *testing.T) {
+	var b Builder
+	config := testConfig()
+
+	// Test with a bad value
+	config["ssh_wait_timeout"] = "this is not good"
+	err := b.Prepare(config)
+	if err == nil {
+		t.Fatal("should have error")
+	}
+
+	// Test with a good one
+	config["ssh_wait_timeout"] = "5s"
+	err = b.Prepare(config)
+	if err != nil {
+		t.Fatalf("should not have error: %s", err)
+	}
+}