diff --git a/include/prefix.cpp b/include/prefix.cpp
index 26542a70c..5f02ce66b 100755
--- a/include/prefix.cpp
+++ b/include/prefix.cpp
@@ -189,6 +189,7 @@ void TPrefix::reopen() const
     TBit_array excl, comfiles;
     comfiles.set(LF_PCON);
     comfiles.set(LF_CLIFO);
+    comfiles.set(LF_INDSP);
     comfiles.set(LF_CAUSALI);
     comfiles.set(LF_RCAUSALI);
     int max = closeall(FALSE, excl, comfiles);
@@ -230,6 +231,7 @@ void TPrefix::set(
   int     max = 0;
   comfiles.set(LF_PCON);
   comfiles.set(LF_CLIFO);
+  comfiles.set(LF_INDSP);
   comfiles.set(LF_CAUSALI);
   comfiles.set(LF_RCAUSALI);