diff --git a/src/CLI2.cpp b/src/CLI2.cpp
index e69381aa5..fddc40585 100644
--- a/src/CLI2.cpp
+++ b/src/CLI2.cpp
@@ -330,7 +330,7 @@ void CLI2::add (const std::vector <std::string>& arguments)
   for (const auto& arg : arguments)
     replacement.emplace_back(arg, Lexer::Type::word);
 
-  for (std::size_t i = 1; i < _original_args.size (); ++i)
+  for (unsigned int i = 1; i < _original_args.size (); ++i)
     replacement.push_back (_original_args[i]);
 
   _original_args = replacement;
@@ -385,7 +385,7 @@ void CLI2::lexArguments ()
   // Note: Starts iterating at index 1, because ::handleArg0 has already
   //       processed it.
   bool terminated = false;
-  for (std::size_t i = 1; i < _original_args.size (); ++i)
+  for (unsigned int i = 1; i < _original_args.size (); ++i)
   {
     bool quoted = Lexer::wasQuoted (_original_args[i].attribute ("raw"));
 
@@ -1026,7 +1026,7 @@ void CLI2::parenthesizeOriginalFilter ()
   // Locate the first and last ORIGINAL FILTER args.
   unsigned int firstOriginalFilter = 0;
   unsigned int lastOriginalFilter = 0;
-  for (std::size_t i = 1; i < _args.size (); ++i)
+  for (unsigned int i = 1; i < _args.size (); ++i)
   {
     if (_args[i].hasTag ("FILTER") &&
         _args[i].hasTag ("ORIGINAL"))
@@ -1043,7 +1043,7 @@ void CLI2::parenthesizeOriginalFilter ()
       lastOriginalFilter)
   {
     std::vector <A2> reconstructed;
-    for (std::size_t i = 0; i < _args.size (); ++i)
+    for (unsigned int i = 0; i < _args.size (); ++i)
     {
       if (i == firstOriginalFilter)
       {
@@ -2038,10 +2038,10 @@ void CLI2::defaultCommand ()
           reconstructed.push_back (cmd);
         }
 
-        for (std::size_t i = 1; i < _original_args.size (); ++i)
+        for (unsigned int i = 1; i < _original_args.size (); ++i)
           reconstructedOriginals.push_back (_original_args[i]);
 
-        for (std::size_t i = 1; i < _args.size (); ++i)
+        for (unsigned int i = 1; i < _args.size (); ++i)
           reconstructed.push_back (_args[i]);
 
         _original_args = reconstructedOriginals;
diff --git a/src/TDB2.cpp b/src/TDB2.cpp
index d135cc44e..847681652 100644
--- a/src/TDB2.cpp
+++ b/src/TDB2.cpp
@@ -104,7 +104,7 @@ bool TF2::get (int id, Task& task)
   // pending.data file, the task in question cannot appear earlier than line
   // (id - 1) in the file.  It can, however, appear significantly later because
   // it is not known how recent a GC operation was run.
-  for (std::size_t i = id - 1; i < _tasks.size (); ++i)
+  for (unsigned int i = id - 1; i < _tasks.size (); ++i)
   {
     if (_tasks[i].id == id)
     {
diff --git a/src/ViewTask.cpp b/src/ViewTask.cpp
index 6377b6bf8..ccfe7eaed 100644
--- a/src/ViewTask.cpp
+++ b/src/ViewTask.cpp
@@ -119,13 +119,13 @@ std::string ViewTask::render (std::vector <Task>& data, std::vector <int>& seque
   std::vector <int> minimal;
   std::vector <int> ideal;
 
-  for (std::size_t i = 0; i < _columns.size (); ++i)
+  for (unsigned int i = 0; i < _columns.size (); ++i)
   {
     // Headers factor in to width calculations.
     unsigned int global_min = 0;
     unsigned int global_ideal = global_min;
 
-    for (std::size_t s = 0; s < sequence.size (); ++s)
+    for (unsigned int s = 0; s < sequence.size (); ++s)
     {
       if (static_cast<int>(s) >= _truncate_lines && _truncate_lines != 0)
         break;
@@ -240,7 +240,7 @@ std::string ViewTask::render (std::vector <Task>& data, std::vector <int>& seque
   // Compose column headers.
   unsigned int max_lines = 0;
   std::vector <std::vector <std::string>> headers;
-  for (std::size_t c = 0; c < _columns.size (); ++c)
+  for (unsigned int c = 0; c < _columns.size (); ++c)
   {
     headers.emplace_back();
     _columns[c]->renderHeader (headers[c], widths[c], _sort[c] ? _sort_header : _header);
@@ -265,7 +265,7 @@ std::string ViewTask::render (std::vector <Task>& data, std::vector <int>& seque
   {
     out += left_margin + extra;
 
-    for (std::size_t c = 0; c < _columns.size (); ++c)
+    for (unsigned int c = 0; c < _columns.size (); ++c)
     {
       if (c)
         out += intra;
@@ -293,7 +293,7 @@ std::string ViewTask::render (std::vector <Task>& data, std::vector <int>& seque
   // Compose, render columns, in sequence.
   _rows = 0;
   std::vector <std::vector <std::string>> cells;
-  for (std::size_t s = 0; s < sequence.size (); ++s)
+  for (unsigned int s = 0; s < sequence.size (); ++s)
   {
     max_lines = 0;
 
@@ -310,7 +310,7 @@ std::string ViewTask::render (std::vector <Task>& data, std::vector <int>& seque
       row_color.blend (rule_color);
     }
 
-    for (std::size_t c = 0; c < _columns.size (); ++c)
+    for (unsigned int c = 0; c < _columns.size (); ++c)
     {
       cells.emplace_back();
       _columns[c]->render (cells[c], data[sequence[s]], widths[c], row_color);
@@ -346,7 +346,7 @@ std::string ViewTask::render (std::vector <Task>& data, std::vector <int>& seque
     {
       out += left_margin + (odd ? extra_odd : extra_even);
 
-      for (std::size_t c = 0; c < _columns.size (); ++c)
+      for (unsigned int c = 0; c < _columns.size (); ++c)
       {
         if (c)
         {