diff --git a/cmd/restic/cmd_check.go b/cmd/restic/cmd_check.go
index e7edff39e..1993b3304 100644
--- a/cmd/restic/cmd_check.go
+++ b/cmd/restic/cmd_check.go
@@ -222,7 +222,7 @@ func runCheck(opts CheckOptions, gopts GlobalOptions, args []string) error {
 	dupFound := false
 	for _, hint := range hints {
 		Printf("%v\n", hint)
-		if _, ok := hint.(checker.ErrDuplicatePacks); ok {
+		if _, ok := hint.(*checker.ErrDuplicatePacks); ok {
 			dupFound = true
 		}
 	}
@@ -273,7 +273,7 @@ func runCheck(opts CheckOptions, gopts GlobalOptions, args []string) error {
 
 	for err := range errChan {
 		errorsFound = true
-		if e, ok := err.(checker.TreeError); ok {
+		if e, ok := err.(*checker.TreeError); ok {
 			Warnf("error for tree %v:\n", e.ID.Str())
 			for _, treeErr := range e.Errors {
 				Warnf("  %v\n", treeErr)
diff --git a/internal/checker/checker.go b/internal/checker/checker.go
index 8e49209f5..2ecd1469c 100644
--- a/internal/checker/checker.go
+++ b/internal/checker/checker.go
@@ -63,7 +63,7 @@ type ErrDuplicatePacks struct {
 	Indexes restic.IDSet
 }
 
-func (e ErrDuplicatePacks) Error() string {
+func (e *ErrDuplicatePacks) Error() string {
 	return fmt.Sprintf("pack %v contained in several indexes: %v", e.PackID.Str(), e.Indexes)
 }
 
@@ -73,7 +73,7 @@ type ErrOldIndexFormat struct {
 	restic.ID
 }
 
-func (err ErrOldIndexFormat) Error() string {
+func (err *ErrOldIndexFormat) Error() string {
 	return fmt.Sprintf("index %v has old format", err.ID.Str())
 }
 
@@ -93,7 +93,7 @@ func (c *Checker) LoadIndex(ctx context.Context) (hints []error, errs []error) {
 
 		if oldFormat {
 			debug.Log("index %v has old format", id.Str())
-			hints = append(hints, ErrOldIndexFormat{id})
+			hints = append(hints, &ErrOldIndexFormat{id})
 		}
 
 		err = errors.Wrapf(err, "error loading index %v", id.Str())
@@ -137,7 +137,7 @@ func (c *Checker) LoadIndex(ctx context.Context) (hints []error, errs []error) {
 	for packID := range c.packs {
 		debug.Log("  check pack %v: contained in %d indexes", packID, len(packToIndex[packID]))
 		if len(packToIndex[packID]) > 1 {
-			hints = append(hints, ErrDuplicatePacks{
+			hints = append(hints, &ErrDuplicatePacks{
 				PackID:  packID,
 				Indexes: packToIndex[packID],
 			})
@@ -257,7 +257,7 @@ type TreeError struct {
 	Errors []error
 }
 
-func (e TreeError) Error() string {
+func (e *TreeError) Error() string {
 	return fmt.Sprintf("tree %v: %v", e.ID.Str(), e.Errors)
 }
 
@@ -276,7 +276,7 @@ func (c *Checker) checkTreeWorker(ctx context.Context, trees <-chan restic.TreeI
 		if len(errs) == 0 {
 			continue
 		}
-		treeError := TreeError{ID: job.ID, Errors: errs}
+		treeError := &TreeError{ID: job.ID, Errors: errs}
 		select {
 		case <-ctx.Done():
 			return
diff --git a/internal/checker/checker_test.go b/internal/checker/checker_test.go
index 2a4384b15..f2ee0c732 100644
--- a/internal/checker/checker_test.go
+++ b/internal/checker/checker_test.go
@@ -289,7 +289,7 @@ func TestDuplicatePacksInIndex(t *testing.T) {
 
 	found := false
 	for _, hint := range hints {
-		if _, ok := hint.(checker.ErrDuplicatePacks); ok {
+		if _, ok := hint.(*checker.ErrDuplicatePacks); ok {
 			found = true
 		} else {
 			t.Errorf("got unexpected hint: %v", hint)