diff --git a/cmd/restic/cmd_check.go b/cmd/restic/cmd_check.go
index 1bc9da687..093a1ac99 100644
--- a/cmd/restic/cmd_check.go
+++ b/cmd/restic/cmd_check.go
@@ -221,11 +221,15 @@ func runCheck(opts CheckOptions, gopts GlobalOptions, args []string) error {
 
 	errorsFound := false
 	suggestIndexRebuild := false
+	mixedFound := false
 	for _, hint := range hints {
 		switch hint.(type) {
 		case *checker.ErrDuplicatePacks, *checker.ErrOldIndexFormat:
 			Printf("%v\n", hint)
 			suggestIndexRebuild = true
+		case *checker.ErrMixedPack:
+			Printf("%v\n", hint)
+			mixedFound = true
 		default:
 			Warnf("error: %v\n", hint)
 			errorsFound = true
@@ -235,6 +239,9 @@ func runCheck(opts CheckOptions, gopts GlobalOptions, args []string) error {
 	if suggestIndexRebuild {
 		Printf("This is non-critical, you can run `restic rebuild-index' to correct this\n")
 	}
+	if mixedFound {
+		Printf("Mixed packs with tree and data blobs are non-critical, you can run `restic prune` to correct this.\n")
+	}
 
 	if len(errs) > 0 {
 		for _, err := range errs {
diff --git a/internal/checker/checker.go b/internal/checker/checker.go
index b972408f5..e479f0aff 100644
--- a/internal/checker/checker.go
+++ b/internal/checker/checker.go
@@ -66,6 +66,15 @@ func (e *ErrDuplicatePacks) Error() string {
 	return fmt.Sprintf("pack %v contained in several indexes: %v", e.PackID, e.Indexes)
 }
 
+// ErrMixedPack is returned when a pack is found that contains both tree and data blobs.
+type ErrMixedPack struct {
+	PackID restic.ID
+}
+
+func (e *ErrMixedPack) Error() string {
+	return fmt.Sprintf("pack %v contains a mix of tree and data blobs", e.PackID.Str())
+}
+
 // ErrOldIndexFormat is returned when an index with the old format is
 // found.
 type ErrOldIndexFormat struct {
@@ -141,6 +150,11 @@ func (c *Checker) LoadIndex(ctx context.Context) (hints []error, errs []error) {
 				Indexes: packToIndex[packID],
 			})
 		}
+		if c.masterIndex.IsMixedPack(packID) {
+			hints = append(hints, &ErrMixedPack{
+				PackID: packID,
+			})
+		}
 	}
 
 	err = c.repo.SetIndex(c.masterIndex)
diff --git a/internal/checker/checker_test.go b/internal/checker/checker_test.go
index 975415a87..c82375e3c 100644
--- a/internal/checker/checker_test.go
+++ b/internal/checker/checker_test.go
@@ -63,6 +63,14 @@ func checkData(chkr *checker.Checker) []error {
 	)
 }
 
+func assertOnlyMixedPackHints(t *testing.T, hints []error) {
+	for _, err := range hints {
+		if _, ok := err.(*checker.ErrMixedPack); !ok {
+			t.Fatalf("expected mixed pack hint, got %v", err)
+		}
+	}
+}
+
 func TestCheckRepo(t *testing.T) {
 	repodir, cleanup := test.Env(t, checkerTestData)
 	defer cleanup()
@@ -74,9 +82,9 @@ func TestCheckRepo(t *testing.T) {
 	if len(errs) > 0 {
 		t.Fatalf("expected no errors, got %v: %v", len(errs), errs)
 	}
-
-	if len(hints) > 0 {
-		t.Errorf("expected no hints, got %v: %v", len(hints), hints)
+	assertOnlyMixedPackHints(t, hints)
+	if len(hints) == 0 {
+		t.Fatal("expected mixed pack warnings, got none")
 	}
 
 	test.OKs(t, checkPacks(chkr))
@@ -100,10 +108,7 @@ func TestMissingPack(t *testing.T) {
 	if len(errs) > 0 {
 		t.Fatalf("expected no errors, got %v: %v", len(errs), errs)
 	}
-
-	if len(hints) > 0 {
-		t.Errorf("expected no hints, got %v: %v", len(hints), hints)
-	}
+	assertOnlyMixedPackHints(t, hints)
 
 	errs = checkPacks(chkr)
 
@@ -136,10 +141,7 @@ func TestUnreferencedPack(t *testing.T) {
 	if len(errs) > 0 {
 		t.Fatalf("expected no errors, got %v: %v", len(errs), errs)
 	}
-
-	if len(hints) > 0 {
-		t.Errorf("expected no hints, got %v: %v", len(hints), hints)
-	}
+	assertOnlyMixedPackHints(t, hints)
 
 	errs = checkPacks(chkr)
 
@@ -181,10 +183,7 @@ func TestUnreferencedBlobs(t *testing.T) {
 	if len(errs) > 0 {
 		t.Fatalf("expected no errors, got %v: %v", len(errs), errs)
 	}
-
-	if len(hints) > 0 {
-		t.Errorf("expected no hints, got %v: %v", len(hints), hints)
-	}
+	assertOnlyMixedPackHints(t, hints)
 
 	test.OKs(t, checkPacks(chkr))
 	test.OKs(t, checkStruct(chkr))
@@ -269,9 +268,7 @@ func TestModifiedIndex(t *testing.T) {
 		t.Logf("found expected error %v", err)
 	}
 
-	if len(hints) > 0 {
-		t.Errorf("expected no hints, got %v: %v", len(hints), hints)
-	}
+	assertOnlyMixedPackHints(t, hints)
 }
 
 var checkerDuplicateIndexTestData = filepath.Join("testdata", "duplicate-packs-in-index-test-repo.tar.gz")
@@ -421,10 +418,7 @@ func TestCheckerNoDuplicateTreeDecodes(t *testing.T) {
 	if len(errs) > 0 {
 		t.Fatalf("expected no errors, got %v: %v", len(errs), errs)
 	}
-
-	if len(hints) > 0 {
-		t.Errorf("expected no hints, got %v: %v", len(hints), hints)
-	}
+	assertOnlyMixedPackHints(t, hints)
 
 	test.OKs(t, checkPacks(chkr))
 	test.OKs(t, checkStruct(chkr))
@@ -572,8 +566,10 @@ func loadBenchRepository(t *testing.B) (*checker.Checker, restic.Repository, fun
 		t.Fatalf("expected no errors, got %v: %v", len(errs), errs)
 	}
 
-	if len(hints) > 0 {
-		t.Errorf("expected no hints, got %v: %v", len(hints), hints)
+	for _, err := range hints {
+		if _, ok := err.(*checker.ErrMixedPack); !ok {
+			t.Fatalf("expected mixed pack hint, got %v", err)
+		}
 	}
 	return chkr, repo, cleanup
 }