diff --git a/include/prefix.cpp b/include/prefix.cpp
index 95cb2de93..26e84f468 100755
--- a/include/prefix.cpp
+++ b/include/prefix.cpp
@@ -167,7 +167,7 @@ HIDDEN void openall(bool changestudy, TBit_array& excl, int oldmax, TBit_array&
         *isfd->r = *r.rec();
         if (excllock(CInsPref((char*) glockname, NORDIR), FALSE) == -1 && errno == EACCES)
           fatal_box("Can't reopen file n. %d : file in use", i + 1);
-        isfd->fhnd = DB_open(isfd->d->SysName, excl[i]);
+        isfd->fhnd = DB_open(isfd->d->SysName, excl[i],TRUE);
         if (isfd->fhnd < 0 ) err=get_error(isfd->fhnd);
         else err = NOERR;
         if (err == _islocked)