diff --git a/src/import.c b/src/import.c
index c7a63fac..20d1d7b6 100644
--- a/src/import.c
+++ b/src/import.c
@@ -125,8 +125,8 @@ int import_message(char *filename, struct session_data *sdata, struct __data *da
 }
 
 
-unsigned long get_folder_id(struct session_data *sdata, struct __data *data, char *foldername, int parent_id){
-   unsigned long id=0;
+int get_folder_id(struct session_data *sdata, struct __data *data, char *foldername, int parent_id){
+   int id=-1;
 
    if(prepare_sql_statement(sdata, &(data->stmt_get_folder_id), SQL_PREPARED_STMT_GET_FOLDER_ID) == ERR) return id;
 
@@ -149,8 +149,8 @@ unsigned long get_folder_id(struct session_data *sdata, struct __data *data, cha
 }
 
 
-unsigned long add_new_folder(struct session_data *sdata, struct __data *data, char *foldername, int parent_id){
-   unsigned long id=0;
+int add_new_folder(struct session_data *sdata, struct __data *data, char *foldername, int parent_id){
+   int id=0;
 
    if(prepare_sql_statement(sdata, &(data->stmt_insert_into_folder_table), SQL_PREPARED_STMT_INSERT_INTO_FOLDER_TABLE) == ERR) return id;
 
diff --git a/src/piler.h b/src/piler.h
index c1f47d81..b5aa7ecb 100644
--- a/src/piler.h
+++ b/src/piler.h
@@ -55,8 +55,8 @@ int retrieve_email_from_archive(struct session_data *sdata, struct __data *data,
 int file_from_archive_to_network(char *filename, int sd, int tls_enable, struct __data *data, struct __config *cfg);
 
 int import_message(char *filename, struct session_data *sdata, struct __data *data, struct __config *cfg);
-unsigned long get_folder_id(struct session_data *sdata, struct __data *data, char *foldername, int parent_id);
-unsigned long add_new_folder(struct session_data *sdata, struct __data *data, char *foldername, int parent_id);
+int get_folder_id(struct session_data *sdata, struct __data *data, char *foldername, int parent_id);
+int add_new_folder(struct session_data *sdata, struct __data *data, char *foldername, int parent_id);
 
 int store_index_data(struct session_data *sdata, struct _state *state, struct __data *data, uint64 id, struct __config *cfg);
 
diff --git a/src/pilerimport.c b/src/pilerimport.c
index 2b8cc8c3..be08af54 100644
--- a/src/pilerimport.c
+++ b/src/pilerimport.c
@@ -543,11 +543,11 @@ int main(int argc, char **argv){
    if(folder){
       data.folder = get_folder_id(&sdata, &data, folder, 0);
 
-      if(data.folder == 0){
+      if(data.folder == -1){
          data.folder = add_new_folder(&sdata, &data, folder, 0);
       }
 
-      if(data.folder == 0){
+      if(data.folder == -1){
          printf("error: cannot get/add folder '%s'\n", folder);
          close_database(&sdata);
          return 0;