diff --git a/src/compute_chunk_atom.cpp b/src/compute_chunk_atom.cpp
index d83643b047..9a4c0c5c9e 100644
--- a/src/compute_chunk_atom.cpp
+++ b/src/compute_chunk_atom.cpp
@@ -548,7 +548,7 @@ void ComputeChunkAtom::compute_peratom()
    set lock, so that nchunk will not change from startstep to stopstep
    called by fix ave/chunk for duration of its Nfreq epoch
    OK if called by multiple fix ave/chunk commands
-     error if all callers do not have same duration
+     but error if all callers do not have same duration
      last caller holds the lock, so it can also unlock
    lockstop can be positive for final step of finite-size time window
    or can be -1 for infinite-size time window
diff --git a/src/fix_ave_chunk.cpp b/src/fix_ave_chunk.cpp
index 4f5ecc02ff..c173b0a8dc 100644
--- a/src/fix_ave_chunk.cpp
+++ b/src/fix_ave_chunk.cpp
@@ -297,7 +297,8 @@ FixAveChunk::FixAveChunk(LAMMPS *lmp, int narg, char **arg) :
   }
 
   // increment lock counter in compute chunk/atom
-  // only if nrepeat > 1, so that locking spans multiple timesteps 
+  // only if nrepeat > 1 or ave = RUNNING/WINDOW,
+  //  so that locking spans multiple timesteps 
 
   int icompute = modify->find_compute(idchunk);
   if (icompute < 0)
@@ -305,7 +306,9 @@ FixAveChunk::FixAveChunk(LAMMPS *lmp, int narg, char **arg) :
   cchunk = (ComputeChunkAtom *) modify->compute[icompute];
   if (strcmp(cchunk->style,"chunk/atom") != 0)
     error->all(FLERR,"Fix ave/chunk does not use chunk/atom compute");
-  if (nrepeat > 1) cchunk->lockcount++;
+
+  if (nrepeat > 1 || ave == RUNNING || ave == WINDOW) cchunk->lockcount++;
+  if (ave == RUNNING || ave == WINDOW) cchunk->lock(this,update->ntimestep,-1);
 
   // print file comment lines
 
@@ -409,10 +412,11 @@ FixAveChunk::~FixAveChunk()
 
   // decrement lock counter in compute chunk/atom, it if still exists
 
-  if (nrepeat > 1) {
+  if (nrepeat > 1 || ave == RUNNING || ave == WINDOW) {
     int icompute = modify->find_compute(idchunk);
     if (icompute >= 0) {
       cchunk = (ComputeChunkAtom *) modify->compute[icompute];
+      if (ave == RUNNING || ave == WINDOW) cchunk->unlock(this);
       cchunk->lockcount--;
     }
   }
@@ -515,8 +519,7 @@ void FixAveChunk::end_of_step()
   // zero out arrays that accumulate over many samples, but not across epochs
   // invoke setup_chunks() to determine current nchunk
   //   re-allocate per-chunk arrays if needed
-  // then invoke lock() so nchunk cannot change until Nfreq epoch is over
-  //   use final arg = -1 for infinite-time window
+  // invoke lock() so nchunk cannot change until Nfreq epoch is over
   // wrap setup_chunks in clearstep/addstep b/c it may invoke computes
   //   both nevery and nfreq are future steps, 
   //   since call below to cchunk->ichunk() 
@@ -530,8 +533,8 @@ void FixAveChunk::end_of_step()
       modify->addstep_compute(ntimestep+nfreq);
     }
     allocate();
-    if (ave == RUNNING || ave == WINDOW) cchunk->lock(this,ntimestep,-1);
-    else cchunk->lock(this,ntimestep,ntimestep+(nrepeat-1)*nevery);
+    if (nrepeat > 1 && ave == ONE) 
+      cchunk->lock(this,ntimestep,ntimestep+(nrepeat-1)*nevery);
     for (m = 0; m < nchunk; m++) {
       count_many[m] = count_sum[m] = 0.0;
       for (i = 0; i < nvalues; i++) values_many[m][i] = 0.0;
@@ -762,7 +765,7 @@ void FixAveChunk::end_of_step()
   // unlock compute chunk/atom at end of Nfreq epoch
   // do not unlock if ave = RUNNING or WINDOW
 
-  if (ave == ONE) cchunk->unlock(this);
+  if (nrepeat > 1 && ave == ONE) cchunk->unlock(this);
 
   // time average across samples
   // if normflag = ALL, final is total value / total count
diff --git a/src/fix_ave_time.cpp b/src/fix_ave_time.cpp
index a651a77813..c06825b71c 100644
--- a/src/fix_ave_time.cpp
+++ b/src/fix_ave_time.cpp
@@ -276,11 +276,14 @@ FixAveTime::FixAveTime(LAMMPS *lmp, int narg, char **arg) :
   // enable locking of row count by this fix for computes of variable length
   // only if nrepeat > 1, so that locking spans multiple timesteps 
 
-  if (any_variable_length && nrepeat > 1) {
+  if (any_variable_length && 
+      (nrepeat > 1 || ave == RUNNING || ave == WINDOW)) {
     for (int i = 0; i < nvalues; i++)
       if (varlen[i]) {
         int icompute = modify->find_compute(ids[i]);
         modify->compute[icompute]->lock_enable();
+        if (ave == RUNNING || ave == WINDOW) 
+          modify->compute[icompute]->lock(this,update->ntimestep,-1);
       }
   }
     
@@ -453,13 +456,17 @@ FixAveTime::FixAveTime(LAMMPS *lmp, int narg, char **arg) :
 FixAveTime::~FixAveTime()
 {
   // decrement lock counter in compute chunk/atom, it if still exists
-  // NOTE: better comment
 
-  if (any_variable_length && nrepeat > 1) {
+  if (any_variable_length && 
+      (nrepeat > 1 || ave == RUNNING || ave == WINDOW)) {
     for (int i = 0; i < nvalues; i++)
       if (varlen[i]) {
         int icompute = modify->find_compute(ids[i]);
-        if (icompute >= 0) modify->compute[icompute]->lock_disable();
+        if (icompute >= 0) {
+          if (ave == RUNNING || ave == WINDOW) 
+            modify->compute[icompute]->unlock(this);
+          modify->compute[icompute]->lock_disable();
+        }
       }
   }
 
@@ -732,9 +739,10 @@ void FixAveTime::invoke_vector(bigint ntimestep)
       bigint ntimestep = update->ntimestep;
       for (i = 0; i < nvalues; i++) {
         if (!varlen[i]) continue;
-        Compute *compute = modify->compute[value2index[i]];
-        if (ave == RUNNING || ave == WINDOW) compute->lock(this,ntimestep,-1);
-        else compute->lock(this,ntimestep,ntimestep+(nrepeat-1)*nevery);
+        if (nrepeat > 1 && ave == ONE) {
+          Compute *compute = modify->compute[value2index[i]];
+          compute->lock(this,ntimestep,ntimestep+(nrepeat-1)*nevery);
+        }
       }
     }
 
@@ -817,7 +825,7 @@ void FixAveTime::invoke_vector(bigint ntimestep)
   // unlock any variable length computes at end of Nfreq epoch
   // do not unlock if ave = RUNNING or WINDOW
 
-  if (any_variable_length && ave == ONE) {
+  if (any_variable_length && nrepeat > 1 && ave == ONE) {
     for (i = 0; i < nvalues; i++) {
       if (!varlen[i]) continue;
       Compute *compute = modify->compute[value2index[i]];