diff --git a/pkg/api/config/config.go b/pkg/api/config/config.go
index 46f6acfe..003469ca 100644
--- a/pkg/api/config/config.go
+++ b/pkg/api/config/config.go
@@ -289,7 +289,9 @@ func New() *Config {
 				GC:         true,
 				GCDelay:    storageConstants.DefaultGCDelay,
 				GCInterval: storageConstants.DefaultGCInterval,
-				Retention:  ImageRetention{},
+				Retention: ImageRetention{
+					Delay: storageConstants.DefaultRetentionDelay,
+				},
 			},
 		},
 		HTTP: HTTPConfig{Address: "127.0.0.1", Port: "8080", Auth: &AuthConfig{FailDelay: 0}},
diff --git a/pkg/cli/server/root.go b/pkg/cli/server/root.go
index 1fc674c0..2ce32f3c 100644
--- a/pkg/cli/server/root.go
+++ b/pkg/cli/server/root.go
@@ -648,6 +648,7 @@ func applyDefaultValues(config *config.Config, viperInstance *viper.Viper, log z
 		}
 	}
 
+	// set default values in case GC is disabled
 	if !config.Storage.GC {
 		if viperInstance.Get("storage::gcdelay") == nil {
 			config.Storage.GCDelay = 0
diff --git a/pkg/retention/retention.go b/pkg/retention/retention.go
index fe9e0e24..510f19ba 100644
--- a/pkg/retention/retention.go
+++ b/pkg/retention/retention.go
@@ -54,8 +54,8 @@ func (p policyManager) HasDeleteUntagged(repo string) bool {
 		return true
 	}
 
-	// default
-	return false
+	// by default zot deletes untagged manifests if the config does not contain retention settings and gc is enabled
+	return true
 }
 
 func (p policyManager) HasDeleteReferrer(repo string) bool {
diff --git a/pkg/storage/gc/gc_test.go b/pkg/storage/gc/gc_test.go
index 3e3ffcfb..6a0866aa 100644
--- a/pkg/storage/gc/gc_test.go
+++ b/pkg/storage/gc/gc_test.go
@@ -1108,7 +1108,7 @@ func TestGarbageCollectAndRetentionMetaDB(t *testing.T) {
 					So(err, ShouldBeNil)
 
 					_, _, _, err = imgStore.GetImageManifest("gc-test1", gcUntagged1.DigestStr())
-					So(err, ShouldBeNil)
+					So(err, ShouldNotBeNil)
 
 					_, _, _, err = imgStore.GetImageManifest("gc-test1", ref1.DigestStr())
 					So(err, ShouldBeNil)
@@ -1319,6 +1319,7 @@ func TestGarbageCollectDeletion(t *testing.T) {
 		metrics := monitoring.NewMetricsServer(false, log)
 
 		trueVal := true
+		falseVal := false
 
 		// Create temporary directory
 		rootDir := t.TempDir()
@@ -1536,6 +1537,80 @@ func TestGarbageCollectDeletion(t *testing.T) {
 				So(err, ShouldNotBeNil)
 			})
 
+			Convey("do not gc untagged manifests after deleting the tag of the top index", func() {
+				gc := gc.NewGarbageCollect(imgStore, metaDB, gc.Options{
+					Delay: 1 * time.Millisecond,
+					ImageRetention: config.ImageRetention{
+						Delay: 1 * time.Millisecond,
+						Policies: []config.RetentionPolicy{
+							{
+								Repositories:    []string{"**"},
+								DeleteReferrers: true,
+								DeleteUntagged:  &falseVal,
+								KeepTags:        []config.KeepTagsPolicy{},
+							},
+						},
+					},
+				}, audit, log)
+
+				err = deleteTagInStorage(rootDir, repoName, "topindex")
+
+				err = gc.CleanRepo(ctx, repoName)
+				So(err, ShouldBeNil)
+
+				// manifest1, bottomIndex1 and topIndex are untagged, so manifest1 should not be deleted
+				tags, err := readTagsFromStorage(rootDir, repoName, manifest1Digest)
+				So(err, ShouldBeNil)
+				So(tags, ShouldContain, "")
+				So(len(tags), ShouldEqual, 1)
+
+				_, err = os.Stat(path.Join(blobsDir, manifest1Digest.Algorithm().String(), manifest1Digest.Encoded()))
+				So(err, ShouldBeNil)
+
+				// manifest2 is has a tag, so it should not be deleted
+				tags, err = readTagsFromStorage(rootDir, repoName, manifest2Digest)
+				So(err, ShouldBeNil)
+				So(tags, ShouldContain, "manifest2")
+				So(len(tags), ShouldEqual, 1)
+
+				_, err = os.Stat(path.Join(blobsDir, manifest2Digest.Algorithm().String(), manifest2Digest.Encoded()))
+				So(err, ShouldBeNil)
+
+				// manifest3 is referenced by tagged bottomIndex2, so it should not be deleted
+				tags, err = readTagsFromStorage(rootDir, repoName, manifest3Digest)
+				So(err, ShouldBeNil)
+				So(tags, ShouldContain, "")
+				So(len(tags), ShouldEqual, 1)
+
+				_, err = os.Stat(path.Join(blobsDir, manifest3Digest.Algorithm().String(), manifest3Digest.Encoded()))
+				So(err, ShouldBeNil)
+
+				// bottomIndex1 and topIndex are untagged, so bottomIndex1 should not be deleted
+				_, err = readTagsFromStorage(rootDir, repoName, bottomIndex1Digest)
+				So(err, ShouldBeNil)
+
+				_, err = os.Stat(path.Join(blobsDir, bottomIndex1Digest.Algorithm().String(), bottomIndex1Digest.Encoded()))
+				So(err, ShouldBeNil)
+
+				// bottomIndex2 is has a tag, so it should not be deleted
+				tags, err = readTagsFromStorage(rootDir, repoName, bottomIndex2Digest)
+				So(err, ShouldBeNil)
+				So(tags, ShouldContain, "bottomIndex2")
+				So(len(tags), ShouldEqual, 1)
+
+				_, err = os.Stat(path.Join(blobsDir, bottomIndex2Digest.Algorithm().String(), bottomIndex2Digest.Encoded()))
+				So(err, ShouldBeNil)
+
+				// topIndex is untagged, so it should not be deleted
+				tags, err = readTagsFromStorage(rootDir, repoName, rootIndexDigest)
+				So(err, ShouldBeNil)
+				So(tags, ShouldContain, "")
+				So(len(tags), ShouldEqual, 1)
+
+				_, err = os.Stat(path.Join(blobsDir, rootIndexDigest.Algorithm().String(), rootIndexDigest.Encoded()))
+				So(err, ShouldBeNil)
+			})
+
 			Convey("gc unmatching tags", func() {
 				gc := gc.NewGarbageCollect(imgStore, metaDB, gc.Options{
 					Delay: 1 * time.Millisecond,
@@ -2414,7 +2489,7 @@ func TestGarbageCollectAndRetentionNoMetaDB(t *testing.T) {
 					So(err, ShouldBeNil)
 
 					_, _, _, err = imgStore.GetImageManifest("gc-test1", gcUntagged1.DigestStr())
-					So(err, ShouldBeNil)
+					So(err, ShouldNotBeNil)
 
 					_, _, _, err = imgStore.GetImageManifest("gc-test1", ref1.DigestStr())
 					So(err, ShouldBeNil)