diff --git a/src/core/ActionAtomistic.cpp b/src/core/ActionAtomistic.cpp
index e798d4a415342382151aaba9c4d1bd75c23a2dde..0dfc93d0ee0cd845f87cc823d6ecf11a561f568e 100644
--- a/src/core/ActionAtomistic.cpp
+++ b/src/core/ActionAtomistic.cpp
@@ -51,7 +51,7 @@ donotforce(false),
 atoms(plumed.getAtoms())
 {
   atoms.add(this);
-  if(atoms.getNatoms()==0) error("Cannot perform calculations involving atoms without atoms");
+//  if(atoms.getNatoms()==0) error("Cannot perform calculations involving atoms without atoms");
 }
 
 void ActionAtomistic::registerKeywords( Keywords& keys ){