diff --git a/src/DebugCmds.cc b/src/DebugCmds.cc
index 57d85a3647..83a485a60a 100644
--- a/src/DebugCmds.cc
+++ b/src/DebugCmds.cc
@@ -83,7 +83,7 @@ static void choose_global_symbols_regex(const string& regex, vector<zeek::detail
 		zeek::detail::debug_msg("There were multiple matches, please choose:\n");
 
 		for ( size_t i = 0; i < choices.size(); i++ )
-			zeek::detail::debug_msg("[%lu] %s\n", i+1, choices[i]->Name());
+			zeek::detail::debug_msg("[%zu] %s\n", i+1, choices[i]->Name());
 
 		zeek::detail::debug_msg("[a] All of the above\n");
 		zeek::detail::debug_msg("[n] None of the above\n");
diff --git a/src/Dict.cc b/src/Dict.cc
index 6eee1ef840..626967beee 100644
--- a/src/Dict.cc
+++ b/src/Dict.cc
@@ -446,7 +446,7 @@ void Dictionary::DumpKeys() const
 	DistanceStats(max_distance);
 	if ( binary )
 		{
-		sprintf(key_file, "%d.%d.%lu-%c.key", Length(), max_distance, MemoryAllocation()/Length(), rand()%26 + 'A');
+		sprintf(key_file, "%d.%d.%zu-%c.key", Length(), max_distance, MemoryAllocation()/Length(), rand()%26 + 'A');
 		std::ofstream f(key_file, std::ios::binary|std::ios::out|std::ios::trunc);
 		for ( int idx = 0; idx < Capacity(); idx++ )
 			if ( ! table[idx].Empty() )
@@ -458,7 +458,7 @@ void Dictionary::DumpKeys() const
 		}
 	else
 		{
-		sprintf(key_file, "%d.%d.%lu-%d.ckey",Length(), max_distance, MemoryAllocation()/Length(), rand()%26 + 'A');
+		sprintf(key_file, "%d.%d.%zu-%d.ckey",Length(), max_distance, MemoryAllocation()/Length(), rand()%26 + 'A');
 		std::ofstream f(key_file, std::ios::out|std::ios::trunc);
 		for ( int idx = 0; idx < Capacity(); idx++ )
 			if ( ! table[idx].Empty() )
@@ -506,7 +506,7 @@ void Dictionary::Dump(int level) const
 	int distances[DICT_NUM_DISTANCES];
 	int max_distance = 0;
 	DistanceStats(max_distance, distances, DICT_NUM_DISTANCES);
-	printf("cap %'7d ent %'7d %'-7d load %.2f max_dist %2d mem %10zu mem/ent %3lu key/ent %3d lg %2d remaps %1d remap_end %4d ",
+	printf("cap %'7d ent %'7d %'-7d load %.2f max_dist %2d mem %10zu mem/ent %3zu key/ent %3d lg %2d remaps %1d remap_end %4d ",
 		Capacity(), Length(), MaxLength(), (double)Length()/(table? Capacity() : 1),
 		max_distance, MemoryAllocation(), (MemoryAllocation())/(Length()?Length():1), key_size / (Length()?Length():1),
 		log2_buckets, remaps, remap_end);
diff --git a/src/broker/Manager.cc b/src/broker/Manager.cc
index 358028d82c..c83b75abde 100644
--- a/src/broker/Manager.cc
+++ b/src/broker/Manager.cc
@@ -1198,7 +1198,7 @@ void Manager::ProcessEvent(const broker::topic& topic, broker::zeek::Event ev)
 			{
 			auto expected_name = zeek::type_name(expected_type->Tag());
 
-	        zeek::reporter->Warning("failed to convert remote event '%s' arg #%lu,"
+	        zeek::reporter->Warning("failed to convert remote event '%s' arg #%zu,"
 	                                " got %s, expected %s",
 	                                name.data(), i, got_type,
 	                                expected_name);
@@ -1268,7 +1268,7 @@ bool bro_broker::Manager::ProcessLogCreate(broker::zeek::LogCreate lc)
 			fields[i] = field;
 		else
 			{
-			zeek::reporter->Warning("failed to convert remote log field # %lu", i);
+			zeek::reporter->Warning("failed to convert remote log field # %zu", i);
 			delete [] fields;
 			return false;
 			}
diff --git a/src/util.cc b/src/util.cc
index 7ddcd6b833..417aed4d2b 100644
--- a/src/util.cc
+++ b/src/util.cc
@@ -1148,7 +1148,8 @@ void init_random_seed(const char* read_file, const char* write_file,
 #endif
 
 		if ( pos < zeek::detail::KeyedHash::SEED_INIT_SIZE )
-			zeek::reporter->FatalError("Could not read enough random data. Wanted %d, got %lu", zeek::detail::KeyedHash::SEED_INIT_SIZE, pos);
+			zeek::reporter->FatalError("Could not read enough random data. Wanted %d, got %zu",
+			                           zeek::detail::KeyedHash::SEED_INIT_SIZE, pos);
 
 		if ( ! seed )
 			{