diff --git a/src/fix_neigh_history.cpp b/src/fix_neigh_history.cpp
index 7413b590a7..613716c9a4 100644
--- a/src/fix_neigh_history.cpp
+++ b/src/fix_neigh_history.cpp
@@ -351,7 +351,9 @@ void FixNeighHistory::pre_exchange_newton()
   // 1st loop over neighbor list
   // calculate npartner for owned+ghost atoms
 
-  for (i = 0; i < nall_neigh; i++) npartner[i] = 0;
+  // Ensure npartner is zeroed across all atoms, nall_neigh can be less than nall
+  // when writing restarts when comm calls are made but modify->post_neighbor() isn't
+  for (i = 0; i < MAX(nall_neigh, atom->nall); i++) npartner[i] = 0;
 
   tagint *tag = atom->tag;
   NeighList *list = pair->list;
@@ -406,7 +408,7 @@ void FixNeighHistory::pre_exchange_newton()
   // store partner IDs and values for owned+ghost atoms
   // re-zero npartner to use as counter
 
-  for (i = 0; i < nall_neigh; i++) npartner[i] = 0;
+  for (i = 0; i < MAX(nall_neigh, atom->nall); i++) npartner[i] = 0;
 
   for (ii = 0; ii < inum; ii++) {
     i = ilist[ii];