diff --git a/admin/sync/exercice_files.go b/admin/sync/exercice_files.go
index ee676993..ee6de6cd 100644
--- a/admin/sync/exercice_files.go
+++ b/admin/sync/exercice_files.go
@@ -71,12 +71,14 @@ func SyncExerciceFiles(i Importer, exercice fic.Exercice) (errs []string) {
 				continue
 			}
 
-			if _, err := i.importFile(path.Join(exercice.Path, "files", fname),
+			if f, err := i.importFile(path.Join(exercice.Path, "files", fname),
 				func(filePath string, origin string) (interface{}, error) {
 					return exercice.ImportFile(filePath, origin, digests[fname])
 				}); err != nil {
 					errs = append(errs, fmt.Sprintf("%q: unable to import file %q: %s", path.Base(exercice.Path), fname, err))
 					continue
+				} else if f.(fic.EFile).Size == 0 {
+					errs = append(errs, fmt.Sprintf("%q: WARNING imported file %q is empty!", path.Base(exercice.Path), fname))
 				}
 		}
 	}