diff --git a/backend/memory/memory.go b/backend/memory/memory.go
index 11c02d78a..608f42292 100644
--- a/backend/memory/memory.go
+++ b/backend/memory/memory.go
@@ -38,8 +38,7 @@ func init() {
 }
 
 // Options defines the configuration for this backend
-type Options struct {
-}
+type Options struct{}
 
 // Fs represents a remote memory server
 type Fs struct {
@@ -385,10 +384,22 @@ func (f *Fs) List(ctx context.Context, dir string) (entries fs.DirEntries, err e
 func (f *Fs) ListR(ctx context.Context, dir string, callback fs.ListRCallback) (err error) {
 	bucket, directory := f.split(dir)
 	list := walk.NewListRHelper(callback)
+	entries := fs.DirEntries{}
 	listR := func(bucket, directory, prefix string, addBucket bool) error {
-		return f.list(ctx, bucket, directory, prefix, addBucket, true, func(remote string, entry fs.DirEntry, isDirectory bool) error {
-			return list.Add(entry)
+		err = f.list(ctx, bucket, directory, prefix, addBucket, true, func(remote string, entry fs.DirEntry, isDirectory bool) error {
+			entries = append(entries, entry) // can't list.Add here -- could deadlock
+			return nil
 		})
+		if err != nil {
+			return err
+		}
+		for _, entry := range entries {
+			err = list.Add(entry)
+			if err != nil {
+				return err
+			}
+		}
+		return nil
 	}
 	if bucket == "" {
 		entries, err := f.listBuckets(ctx)
diff --git a/backend/memory/memory_internal_test.go b/backend/memory/memory_internal_test.go
new file mode 100644
index 000000000..fe8db1f57
--- /dev/null
+++ b/backend/memory/memory_internal_test.go
@@ -0,0 +1,40 @@
+package memory
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	_ "github.com/rclone/rclone/backend/local"
+	"github.com/rclone/rclone/fs/operations"
+	"github.com/rclone/rclone/fstest"
+	"github.com/rclone/rclone/fstest/fstests"
+	"github.com/stretchr/testify/require"
+)
+
+var t1 = fstest.Time("2001-02-03T04:05:06.499999999Z")
+
+// InternalTest dispatches all internal tests
+func (f *Fs) InternalTest(t *testing.T) {
+	t.Run("PurgeListDeadlock", func(t *testing.T) {
+		testPurgeListDeadlock(t)
+	})
+}
+
+// test that Purge fallback does not result in deadlock from concurrently listing and removing
+func testPurgeListDeadlock(t *testing.T) {
+	ctx := context.Background()
+	r := fstest.NewRunIndividual(t)
+	r.Mkdir(ctx, r.Fremote)
+	r.Fremote.Features().Disable("Purge") // force fallback-purge
+
+	// make a lot of files to prevent it from finishing too quickly
+	for i := 0; i < 100; i++ {
+		dst := "file" + fmt.Sprint(i) + ".txt"
+		r.WriteObject(ctx, dst, "hello", t1)
+	}
+
+	require.NoError(t, operations.Purge(ctx, r.Fremote, ""))
+}
+
+var _ fstests.InternalTester = (*Fs)(nil)