diff --git a/doc/src/fix_atom_swap.txt b/doc/src/fix_atom_swap.txt
index 22091eca00..cb6bc26aa1 100644
--- a/doc/src/fix_atom_swap.txt
+++ b/doc/src/fix_atom_swap.txt
@@ -141,11 +141,16 @@ specify if this should be done.
 
 This fix writes the state of the fix to "binary restart
 files"_restart.html.  This includes information about the random
-number generator seed, the next timestep for MC exchanges, etc.  See
+number generator seed, the next timestep for MC exchanges, the number
+of exchange attempts and successes etc.  See
 the "read_restart"_read_restart.html command for info on how to
 re-specify a fix in an input script that reads a restart file, so that
 the operation of the fix continues in an uninterrupted fashion.
 
+NOTE: For this to work correctly, the timestep must [not] be changed
+after reading the restart with "reset_timestep"_reset_timestep.html.
+The fix will try to detect it and stop with an error.
+
 None of the "fix_modify"_fix_modify.html options are relevant to this
 fix.
 
diff --git a/doc/src/fix_deposit.txt b/doc/src/fix_deposit.txt
index fd12d4bb45..9ab125a55f 100644
--- a/doc/src/fix_deposit.txt
+++ b/doc/src/fix_deposit.txt
@@ -261,6 +261,10 @@ next timestep for deposition, etc.  See the
 a fix in an input script that reads a restart file, so that the
 operation of the fix continues in an uninterrupted fashion.
 
+NOTE: For this to work correctly, the timestep must [not] be changed
+after reading the restart with "reset_timestep"_reset_timestep.html.
+The fix will try to detect it and stop with an error.
+
 None of the "fix_modify"_fix_modify.html options are relevant to this
 fix.  No global or per-atom quantities are stored by this fix for
 access by various "output commands"_Howto_output.html.  No parameter
diff --git a/doc/src/fix_gcmc.txt b/doc/src/fix_gcmc.txt
index 8a66a007a3..3c0f2c2f17 100644
--- a/doc/src/fix_gcmc.txt
+++ b/doc/src/fix_gcmc.txt
@@ -373,11 +373,16 @@ adds all inserted atoms of the specified type to the
 
 This fix writes the state of the fix to "binary restart
 files"_restart.html.  This includes information about the random
-number generator seed, the next timestep for MC exchanges, etc.  See
+number generator seed, the next timestep for MC exchanges,  the number
+of MC step attempts and successes etc.  See
 the "read_restart"_read_restart.html command for info on how to
 re-specify a fix in an input script that reads a restart file, so that
 the operation of the fix continues in an uninterrupted fashion.
 
+NOTE: For this to work correctly, the timestep must [not] be changed
+after reading the restart with "reset_timestep"_reset_timestep.html.
+The fix will try to detect it and stop with an error.
+
 None of the "fix_modify"_fix_modify.html options are relevant to this
 fix.
 
diff --git a/src/MC/fix_atom_swap.cpp b/src/MC/fix_atom_swap.cpp
index 12b5d65f4a..7d817ffbb1 100644
--- a/src/MC/fix_atom_swap.cpp
+++ b/src/MC/fix_atom_swap.cpp
@@ -771,10 +771,13 @@ double FixAtomSwap::memory_usage()
 void FixAtomSwap::write_restart(FILE *fp)
 {
   int n = 0;
-  double list[4];
+  double list[6];
   list[n++] = random_equal->state();
   list[n++] = random_unequal->state();
-  list[n++] = next_reneighbor;
+  list[n++] = ubuf(next_reneighbor).d;
+  list[n++] = nswap_attempts;
+  list[n++] = nswap_successes;
+  list[n++] = ubuf(update->ntimestep).d;
 
   if (comm->me == 0) {
     int size = n * sizeof(double);
@@ -798,5 +801,12 @@ void FixAtomSwap::restart(char *buf)
   seed = static_cast<int> (list[n++]);
   random_unequal->reset(seed);
 
-  next_reneighbor = static_cast<int> (list[n++]);
+  next_reneighbor = (bigint) ubuf(list[n++]).i;
+
+  nswap_attempts = static_cast<int>(list[n++]);
+  nswap_successes = static_cast<int>(list[n++]);
+
+  bigint ntimestep_restart = (bigint) ubuf(list[n++]).i;
+  if (ntimestep_restart != update->ntimestep)
+    error->all(FLERR,"Must not reset timestep when restarting fix atom/swap");
 }
diff --git a/src/MC/fix_gcmc.cpp b/src/MC/fix_gcmc.cpp
index f1664e3540..7ab0879335 100644
--- a/src/MC/fix_gcmc.cpp
+++ b/src/MC/fix_gcmc.cpp
@@ -2531,10 +2531,19 @@ double FixGCMC::memory_usage()
 void FixGCMC::write_restart(FILE *fp)
 {
   int n = 0;
-  double list[4];
+  double list[12];
   list[n++] = random_equal->state();
   list[n++] = random_unequal->state();
-  list[n++] = next_reneighbor;
+  list[n++] = ubuf(next_reneighbor).d;
+  list[n++] = ntranslation_attempts;
+  list[n++] = ntranslation_successes;
+  list[n++] = nrotation_attempts;
+  list[n++] = nrotation_successes;
+  list[n++] = ndeletion_attempts;
+  list[n++] = ndeletion_successes;
+  list[n++] = ninsertion_attempts;
+  list[n++] = ninsertion_successes;
+  list[n++] = ubuf(update->ntimestep).d;
 
   if (comm->me == 0) {
     int size = n * sizeof(double);
@@ -2558,7 +2567,20 @@ void FixGCMC::restart(char *buf)
   seed = static_cast<int> (list[n++]);
   random_unequal->reset(seed);
 
-  next_reneighbor = static_cast<int> (list[n++]);
+  next_reneighbor = (bigint) ubuf(list[n++]).i;
+
+  ntranslation_attempts  = list[n++];
+  ntranslation_successes = list[n++];
+  nrotation_attempts     = list[n++];
+  nrotation_successes    = list[n++];
+  ndeletion_attempts     = list[n++];
+  ndeletion_successes    = list[n++];
+  ninsertion_attempts    = list[n++];
+  ninsertion_successes   = list[n++];
+
+  bigint ntimestep_restart = (bigint) ubuf(list[n++]).i;
+  if (ntimestep_restart != update->ntimestep)
+    error->all(FLERR,"Must not reset timestep when restarting fix gcmc");
 }
 
 void FixGCMC::grow_molecule_arrays(int nmolatoms) {
diff --git a/src/MISC/fix_deposit.cpp b/src/MISC/fix_deposit.cpp
index 1428299eb7..66aed34846 100644
--- a/src/MISC/fix_deposit.cpp
+++ b/src/MISC/fix_deposit.cpp
@@ -798,11 +798,12 @@ void FixDeposit::options(int narg, char **arg)
 void FixDeposit::write_restart(FILE *fp)
 {
   int n = 0;
-  double list[4];
+  double list[5];
   list[n++] = random->state();
   list[n++] = ninserted;
   list[n++] = nfirst;
-  list[n++] = next_reneighbor;
+  list[n++] = ubuf(next_reneighbor).d;
+  list[n++] = ubuf(update->ntimestep).d;
 
   if (comm->me == 0) {
     int size = n * sizeof(double);
@@ -823,7 +824,11 @@ void FixDeposit::restart(char *buf)
   seed = static_cast<int> (list[n++]);
   ninserted = static_cast<int> (list[n++]);
   nfirst = static_cast<int> (list[n++]);
-  next_reneighbor = static_cast<int> (list[n++]);
+  next_reneighbor = (bigint) ubuf(list[n++]).i;
+
+  bigint ntimestep_restart = (bigint) ubuf(list[n++]).i;
+  if (ntimestep_restart != update->ntimestep)
+    error->all(FLERR,"Must not reset timestep when restarting this fix");
 
   random->reset(seed);
 }