diff --git a/src/frontend/mame/ui/filesel.cpp b/src/frontend/mame/ui/filesel.cpp
index 94e09207027..187b7175cb0 100644
--- a/src/frontend/mame/ui/filesel.cpp
+++ b/src/frontend/mame/ui/filesel.cpp
@@ -446,7 +446,7 @@ void menu_file_selector::handle()
 					if (cur_selected != &entry)
 					{
 						int match = 0;
-						for (int i = 0; i < m_filename.size(); i++)
+						for (int i = 0; i < m_filename.size() + 1; i++)
 						{
 							if (core_strnicmp(entry.basename.c_str(), m_filename.c_str(), i) == 0)
 								match = i;
diff --git a/src/frontend/mame/ui/swlist.cpp b/src/frontend/mame/ui/swlist.cpp
index 7fbd453217e..df7bc42e2c1 100644
--- a/src/frontend/mame/ui/swlist.cpp
+++ b/src/frontend/mame/ui/swlist.cpp
@@ -280,7 +280,7 @@ void menu_software_list::handle()
 						auto &compare_name = m_ordered_by_shortname ? entry.short_name : entry.long_name;
 
 						int match = 0;
-						for (int i = 0; i < m_filename_buffer.length(); i++)
+						for (int i = 0; i < m_filename_buffer.size() + 1; i++)
 						{
 							if (core_strnicmp(compare_name.c_str(), m_filename_buffer.c_str(), i) == 0)
 								match = i;