diff --git a/src/Options.cc b/src/Options.cc
index f94a986564..d0a651fd7e 100644
--- a/src/Options.cc
+++ b/src/Options.cc
@@ -250,7 +250,7 @@ zeek::Options zeek::parse_cmdline(int argc, char** argv)
 	// getopt may permute the array, so need yet another array
 	auto zargs = std::make_unique<char*[]>(zeek_args.size());
 
-	for ( size_t i = 0u; i < zeek_args.size(); ++i )
+	for ( size_t i = 0; i < zeek_args.size(); ++i )
 		zargs[i] = zeek_args[i].data();
 
 	while ( (op = getopt_long(zeek_args.size(), zargs.get(), opts, long_opts, &long_optsind)) != EOF )
diff --git a/src/analyzer/protocol/rpc/RPC.cc b/src/analyzer/protocol/rpc/RPC.cc
index a29835a9ab..6e16f5ce6c 100644
--- a/src/analyzer/protocol/rpc/RPC.cc
+++ b/src/analyzer/protocol/rpc/RPC.cc
@@ -85,7 +85,7 @@ RPC_CallInfo::RPC_CallInfo(uint32_t arg_xid, const u_char*& buf, int& n, double
 			return;
 			}
 
-		for ( size_t i = 0u; i < number_of_gids; ++i )
+		for ( size_t i = 0; i < number_of_gids; ++i )
 			auxgids.push_back(extract_XDR_uint32(cred_opaque, cred_opaque_n));
 		}
 
diff --git a/src/broker/Data.cc b/src/broker/Data.cc
index 4ece76ef80..260dec8eb6 100644
--- a/src/broker/Data.cc
+++ b/src/broker/Data.cc
@@ -239,7 +239,7 @@ struct val_converter {
 
 			auto list_val = zeek::make_intrusive<zeek::ListVal>(zeek::TYPE_ANY);
 
-			for ( size_t i = 0u; i < indices->size(); ++i )
+			for ( size_t i = 0; i < indices->size(); ++i )
 				{
 				auto index_val = bro_broker::data_to_val(move((*indices)[i]),
 				                                         expected_index_types[i].get());
@@ -298,7 +298,7 @@ struct val_converter {
 
 			auto list_val = zeek::make_intrusive<zeek::ListVal>(zeek::TYPE_ANY);
 
-			for ( size_t i = 0u; i < indices->size(); ++i )
+			for ( size_t i = 0; i < indices->size(); ++i )
 				{
 				auto index_val = bro_broker::data_to_val(move((*indices)[i]),
 				                                         expected_index_types[i].get());
@@ -386,7 +386,7 @@ struct val_converter {
 			auto rval = zeek::make_intrusive<zeek::RecordVal>(zeek::IntrusivePtr{zeek::NewRef{}, rt});
 			auto idx = 0u;
 
-			for ( size_t i = 0u; i < static_cast<size_t>(rt->NumFields()); ++i )
+			for ( size_t i = 0; i < static_cast<size_t>(rt->NumFields()); ++i )
 				{
 				if ( idx >= a.size() )
 					return nullptr;
@@ -574,7 +574,7 @@ struct type_checker {
 						{
 						indices_to_check.reserve(indices->size());
 
-						for ( size_t i = 0u; i < indices->size(); ++i )
+						for ( size_t i = 0; i < indices->size(); ++i )
 							indices_to_check.emplace_back(&(*indices)[i]);
 						}
 					}
@@ -582,7 +582,7 @@ struct type_checker {
 					{
 					indices_to_check.reserve(indices->size());
 
-					for ( size_t i = 0u; i < indices->size(); ++i )
+					for ( size_t i = 0; i < indices->size(); ++i )
 						indices_to_check.emplace_back(&(*indices)[i]);
 					}
 				}
@@ -592,7 +592,7 @@ struct type_checker {
 			if ( expected_index_types.size() != indices_to_check.size() )
 				return false;
 
-			for ( size_t i = 0u; i < indices_to_check.size(); ++i )
+			for ( size_t i = 0; i < indices_to_check.size(); ++i )
 				{
 				auto expect = expected_index_types[i].get();
 				auto& index_to_check = *(indices_to_check)[i];
@@ -633,7 +633,7 @@ struct type_checker {
 						{
 						indices_to_check.reserve(indices->size());
 
-						for ( size_t i = 0u; i < indices->size(); ++i )
+						for ( size_t i = 0; i < indices->size(); ++i )
 							indices_to_check.emplace_back(&(*indices)[i]);
 						}
 					}
@@ -641,7 +641,7 @@ struct type_checker {
 					{
 					indices_to_check.reserve(indices->size());
 
-					for ( size_t i = 0u; i < indices->size(); ++i )
+					for ( size_t i = 0; i < indices->size(); ++i )
 						indices_to_check.emplace_back(&(*indices)[i]);
 					}
 				}
@@ -654,7 +654,7 @@ struct type_checker {
 				return false;
 				}
 
-			for ( size_t i = 0u; i < indices_to_check.size(); ++i )
+			for ( size_t i = 0; i < indices_to_check.size(); ++i )
 				{
 				auto expect = expected_index_types[i].get();
 				auto& index_to_check = *(indices_to_check)[i];
@@ -715,7 +715,7 @@ struct type_checker {
 			auto rt = type->AsRecordType();
 			auto idx = 0u;
 
-			for ( size_t i = 0u; i < static_cast<size_t>(rt->NumFields()); ++i )
+			for ( size_t i = 0; i < static_cast<size_t>(rt->NumFields()); ++i )
 				{
 				if ( idx >= a.size() )
 					return false;
@@ -964,7 +964,7 @@ broker::expected<broker::data> bro_broker::val_to_data(const zeek::Val* v)
 		size_t num_fields = v->GetType()->AsRecordType()->NumFields();
 		rval.reserve(num_fields);
 
-		for ( size_t i = 0u; i < num_fields; ++i )
+		for ( size_t i = 0; i < num_fields; ++i )
 			{
 			auto item_val = rec->GetFieldOrDefault(i);
 
diff --git a/src/broker/Manager.cc b/src/broker/Manager.cc
index 6bafb09a02..db2dc80c5b 100644
--- a/src/broker/Manager.cc
+++ b/src/broker/Manager.cc
@@ -855,7 +855,7 @@ bool Manager::Forward(string topic_prefix)
 
 bool Manager::Unsubscribe(const string& topic_prefix)
 	{
-	for ( size_t i = 0u; i < forwarded_prefixes.size(); ++i )
+	for ( size_t i = 0; i < forwarded_prefixes.size(); ++i )
 		if ( forwarded_prefixes[i] == topic_prefix )
 			{
 			DBG_LOG(DBG_BROKER, "Unforwading topic prefix %s", topic_prefix.c_str());
@@ -1180,7 +1180,7 @@ void Manager::ProcessEvent(const broker::topic& topic, broker::zeek::Event ev)
 	zeek::Args vl;
 	vl.reserve(args.size());
 
-	for ( size_t i = 0u; i < args.size(); ++i )
+	for ( size_t i = 0; i < args.size(); ++i )
 		{
 		auto got_type = args[i].get_type_name();
 		const auto& expected_type = arg_types[i];
@@ -1255,7 +1255,7 @@ bool bro_broker::Manager::ProcessLogCreate(broker::zeek::LogCreate lc)
 	auto num_fields = fields_data->size();
 	auto fields = new threading::Field* [num_fields];
 
-	for ( size_t i = 0u; i < num_fields; ++i )
+	for ( size_t i = 0; i < num_fields; ++i )
 		{
 		if ( auto field = data_to_threading_field(std::move((*fields_data)[i])) )
 			fields[i] = field;