diff --git a/plugin/discovery/find.go b/plugin/discovery/find.go
index 539b9358c5..e42bb49f68 100644
--- a/plugin/discovery/find.go
+++ b/plugin/discovery/find.go
@@ -4,11 +4,14 @@ import (
 	"io/ioutil"
 	"log"
 	"path/filepath"
+	"regexp"
 	"runtime"
 	"strings"
 )
 
-const machineName = runtime.GOOS + "_" + runtime.GOARCH
+// Store the machine name for excluding legacy plugins in new-style directories.
+// This is a var to override in testing
+var machineName = runtime.GOOS + "_" + runtime.GOARCH
 
 // FindPlugins looks in the given directories for files whose filenames
 // suggest that they are plugins of the given kind (e.g. "provider") and
@@ -41,66 +44,53 @@ func FindPluginPaths(kind string, dirs []string) []string {
 	// This is just a thin wrapper around findPluginPaths so that we can
 	// use the latter in tests with a fake machineName so we can use our
 	// test fixtures.
-	return findPluginPaths(kind, machineName, dirs)
+	return findPluginPaths(kind, dirs)
 }
 
-func findPluginPaths(kind string, machineName string, dirs []string) []string {
+func findPluginPaths(kind string, dirs []string) []string {
+	hasMachineSuffix := regexp.MustCompile(machineName + "/?").MatchString
+
 	prefix := "terraform-" + kind + "-"
 
 	ret := make([]string, 0, len(dirs))
 
-	for _, baseDir := range dirs {
-		baseItems, err := ioutil.ReadDir(baseDir)
+	for _, dir := range dirs {
+		items, err := ioutil.ReadDir(dir)
 		if err != nil {
 			// Ignore missing dirs, non-dirs, etc
 			continue
 		}
 
-		log.Printf("[DEBUG] checking for plugins in %q", baseDir)
+		log.Printf("[DEBUG] checking for plugins in %q", dir)
+
+		isMachineDir := hasMachineSuffix(dir)
 
-		for _, item := range baseItems {
+		for _, item := range items {
 			fullName := item.Name()
 
-			if fullName == machineName && item.Mode().IsDir() {
-				// Current-style $GOOS-$GOARCH directory prefix
-				machineDir := filepath.Join(baseDir, machineName)
-				machineItems, err := ioutil.ReadDir(machineDir)
+			if !strings.HasPrefix(fullName, prefix) {
+				log.Printf("[DEBUG] skipping %q, not a plugin", fullName)
+				continue
+			}
+
+			// New-style paths must have a version segment in filename
+			if strings.Contains(strings.ToLower(fullName), "_v") {
+				absPath, err := filepath.Abs(filepath.Join(dir, fullName))
 				if err != nil {
+					log.Printf("[ERROR] plugin filepath error: %s", err)
 					continue
 				}
 
-				log.Printf("[DEBUG] checking for plugins in %q", machineDir)
-
-				for _, item := range machineItems {
-					fullName := item.Name()
-
-					if !strings.HasPrefix(fullName, prefix) {
-						continue
-					}
-
-					// New-style paths must have a version segment in filename
-					if !strings.Contains(strings.ToLower(fullName), "_v") {
-						continue
-					}
-
-					absPath, err := filepath.Abs(filepath.Join(machineDir, fullName))
-					if err != nil {
-						continue
-					}
-
-					log.Printf("[DEBUG] found plugin %q", fullName)
-
-					ret = append(ret, filepath.Clean(absPath))
-				}
-
+				log.Printf("[DEBUG] found plugin %q", fullName)
+				ret = append(ret, filepath.Clean(absPath))
 				continue
 			}
 
-			// FIXME: we pass in GOOS_GOARCH paths directly, so these may not be "legacy"
-			if strings.HasPrefix(fullName, prefix) {
+			if !isMachineDir {
 				// Legacy style with files directly in the base directory
-				absPath, err := filepath.Abs(filepath.Join(baseDir, fullName))
+				absPath, err := filepath.Abs(filepath.Join(dir, fullName))
 				if err != nil {
+					log.Printf("[ERROR] plugin filepath error: %s", err)
 					continue
 				}
 
diff --git a/plugin/discovery/find_test.go b/plugin/discovery/find_test.go
index a788882bb0..58e2946d18 100644
--- a/plugin/discovery/find_test.go
+++ b/plugin/discovery/find_test.go
@@ -7,12 +7,15 @@ import (
 	"testing"
 )
 
+func init() {
+	machineName = "mockos_mockarch"
+}
+
 func TestFindPluginPaths(t *testing.T) {
 	got := findPluginPaths(
 		"foo",
-		"mockos_mockarch",
 		[]string{
-			"test-fixtures/current-style-plugins",
+			"test-fixtures/current-style-plugins/mockos_mockarch",
 			"test-fixtures/legacy-style-plugins",
 			"test-fixtures/non-existent",
 			"test-fixtures/not-a-dir",