diff --git a/Core/GameEngine/Include/Common/FileSystem.h b/Core/GameEngine/Include/Common/FileSystem.h
index 2aaa30a61f1..b71bcaf028a 100644
--- a/Core/GameEngine/Include/Common/FileSystem.h
+++ b/Core/GameEngine/Include/Common/FileSystem.h
@@ -163,6 +163,10 @@ class FileSystem : public SubsystemInterface
 	static bool removeExtension(AsciiString& path);
 	static bool removeExtension(UnicodeString& path);
 
+	/// Appends the native separator to nonempty paths unless either separator is already at the end.
+	/// Existing separators are not converted.
+	static void appendPathSeparator(AsciiString& path);
+
 protected:
 #if ENABLE_FILESYSTEM_EXISTENCE_CACHE
 	struct FileExistData
diff --git a/Core/GameEngine/Source/Common/System/ArchiveFile.cpp b/Core/GameEngine/Source/Common/System/ArchiveFile.cpp
index 1f982b65a1d..c9a4282d271 100644
--- a/Core/GameEngine/Source/Common/System/ArchiveFile.cpp
+++ b/Core/GameEngine/Source/Common/System/ArchiveFile.cpp
@@ -30,6 +30,7 @@
 
 #include "Common/ArchiveFile.h"
 #include "Common/ArchiveFileSystem.h"
+#include "Common/FileSystem.h"
 #include "Common/file.h"
 #include "Common/PerfTimer.h"
 
@@ -157,9 +158,8 @@ void ArchiveFile::getFileListInDirectory(const DetailedArchivedDirectoryInfo *di
 		const DetailedArchivedDirectoryInfo *tempDirInfo = &(diriter->second);
 		AsciiString tempdirname;
 		tempdirname = currentDirectory;
-		if ((!tempdirname.isEmpty()) && (!tempdirname.endsWith("\\"))) {
-			tempdirname.concat('\\');
-		}
+		// TheSuperHackers @fix bobtista 14/08/2026 Avoid adding a separator when either separator is already present.
+		FileSystem::appendPathSeparator(tempdirname);
 		tempdirname.concat(tempDirInfo->m_directoryName);
 		getFileListInDirectory(tempDirInfo, tempdirname, searchName, filenameList, searchSubdirectories);
 		diriter++;
@@ -170,9 +170,7 @@ void ArchiveFile::getFileListInDirectory(const DetailedArchivedDirectoryInfo *di
 		if (SearchStringMatches(fileiter->second.m_filename, searchName)) {
 			AsciiString tempfilename;
 			tempfilename = currentDirectory;
-			if ((!tempfilename.isEmpty()) && (!tempfilename.endsWith("\\"))) {
-				tempfilename.concat('\\');
-			}
+			FileSystem::appendPathSeparator(tempfilename);
 			tempfilename.concat(fileiter->second.m_filename);
 			if (filenameList.find(tempfilename) == filenameList.end()) {
 				// only insert into the list if its not already in there.
diff --git a/Core/GameEngine/Source/Common/System/FileSystem.cpp b/Core/GameEngine/Source/Common/System/FileSystem.cpp
index b8e4c4695b6..39761e41dca 100644
--- a/Core/GameEngine/Source/Common/System/FileSystem.cpp
+++ b/Core/GameEngine/Source/Common/System/FileSystem.cpp
@@ -358,13 +358,9 @@ Bool FileSystem::isPathInDirectory(const AsciiString& testPath, const AsciiStrin
 		return false;
 	}
 
-#ifdef _WIN32
-	const char* pathSep = "\\";
-#else
-	const char* pathSep = "/";
-#endif
+	const char pathSep = getNativePathSeparator();
 
-	if (!basePathNormalized.endsWith(pathSep))
+	if (basePathNormalized.getCharAt(basePathNormalized.getLength() - 1) != pathSep)
 	{
 		basePathNormalized.concat(pathSep);
 	}
@@ -408,3 +404,14 @@ bool FileSystem::removeExtension(UnicodeString& path)
 
 	return false;
 }
+
+//============================================================================
+// FileSystem::appendPathSeparator
+//============================================================================
+void FileSystem::appendPathSeparator(AsciiString& path)
+{
+	if (path.isNotEmpty() && !isPathSeparator(path.getCharAt(path.getLength() - 1)))
+	{
+		path.concat(getNativePathSeparator());
+	}
+}
diff --git a/Core/GameEngine/Source/GameClient/MapUtil.cpp b/Core/GameEngine/Source/GameClient/MapUtil.cpp
index 1806c50741a..d6a69a6d181 100644
--- a/Core/GameEngine/Source/GameClient/MapUtil.cpp
+++ b/Core/GameEngine/Source/GameClient/MapUtil.cpp
@@ -60,6 +60,7 @@
 #include "GameLogic/FPUControl.h"
 #include "GameNetwork/GameInfo.h"
 #include "GameNetwork/NetworkDefs.h"
+#include "Lib/PathUtil.h"
 
 
 //-------------------------------------------------------------------------------
@@ -530,14 +531,13 @@ Bool MapCache::loadMapsFromDisk( const AsciiString &mapDir, Bool isOfficial, Boo
 		AsciiString filepathLower = *filepathIt;
 		filepathLower.toLower();
 
-		const char *szFilenameLower = filepathLower.reverseFind('\\');
+		const char *szFilenameLower = getLastPathSeparator(filepathLower.str());
 		if (!szFilenameLower)
 		{
-			DEBUG_CRASH(("Couldn't find \\ in map name!"));
+			DEBUG_CRASH(("Couldn't find path separator in map name!"));
 			continue;
 		}
 
-		AsciiString endingStr;
 		AsciiString filenameLower = szFilenameLower+1;
 		filenameLower.truncateBy(strlen(mapExtension));
 
@@ -547,7 +547,8 @@ Bool MapCache::loadMapsFromDisk( const AsciiString &mapDir, Bool isOfficial, Boo
 			continue;
 		}
 
-		endingStr.format("%s\\%s%s", filenameLower.str(), filenameLower.str(), mapExtension);
+		AsciiString endingStr;
+		endingStr.format("%s%c%s%s", filenameLower.str(), *szFilenameLower, filenameLower.str(), mapExtension);
 
 		if (!filepathLower.endsWithNoCase(endingStr.str()))
 		{
@@ -591,8 +592,8 @@ Bool MapCache::addMap(
 			if (md.m_nameLookupTag.isEmpty())
 			{
 				// unofficial maps or maps without names
-				AsciiString tempdisplayname;
-				tempdisplayname = fname.reverseFind('\\') + 1;
+				// TheSuperHackers @bugfix bobtista 14/09/2026 Handle map filenames with either separator or no separator.
+				AsciiString tempdisplayname = getFileName(fname.str());
 				(*this)[lowerFname].m_displayName.translate(tempdisplayname);
 				if (md.m_numPlayers >= 2)
 				{
@@ -653,8 +654,7 @@ Bool MapCache::addMap(
 	if (!exists || nameLookupTag.isEmpty())
 	{
 		DEBUG_LOG(("Missing TheKey_mapName!"));
-		AsciiString tempdisplayname;
-		tempdisplayname = fname.reverseFind('\\') + 1;
+		AsciiString tempdisplayname = getFileName(fname.str());
 		md.m_displayName.translate(tempdisplayname);
 		if (md.m_numPlayers >= 2)
 		{
diff --git a/Core/Libraries/Include/Lib/PathUtil.h b/Core/Libraries/Include/Lib/PathUtil.h
index 683f6fee130..ad6c00d6283 100644
--- a/Core/Libraries/Include/Lib/PathUtil.h
+++ b/Core/Libraries/Include/Lib/PathUtil.h
@@ -23,7 +23,8 @@
 #include "BaseType.h"
 #include <string.h>
 
-inline bool isPathSeparator(char ch)
+// Returns true for a separator the host platform uses to open files.
+inline bool isNativePathSeparator(char ch)
 {
 #ifdef _WIN32
 	return ch == '\\' || ch == '/';
@@ -32,6 +33,12 @@ inline bool isPathSeparator(char ch)
 #endif
 }
 
+// Returns true for either separator. Game data paths carry '\\' on every platform.
+inline bool isPathSeparator(char ch)
+{
+	return ch == '/' || ch == '\\';
+}
+
 inline bool isAbsolutePath(const char* path)
 {
 	if (path == nullptr)
@@ -39,14 +46,14 @@ inline bool isAbsolutePath(const char* path)
 		return false;
 	}
 
-	if (isPathSeparator(path[0]))
+	if (isNativePathSeparator(path[0]))
 	{
 		return true;
 	}
 
 #ifdef _WIN32
 	const bool hasDriveLetter = (path[0] >= 'A' && path[0] <= 'Z') || (path[0] >= 'a' && path[0] <= 'z');
-	if (hasDriveLetter && path[1] == ':' && isPathSeparator(path[2]))
+	if (hasDriveLetter && path[1] == ':' && isNativePathSeparator(path[2]))
 	{
 		return true;
 	}
@@ -55,6 +62,32 @@ inline bool isAbsolutePath(const char* path)
 	return false;
 }
 
+inline char getNativePathSeparator()
+{
+#ifdef _WIN32
+	return '\\';
+#else
+	return '/';
+#endif
+}
+
+inline const char* getLastPathSeparator(const char* path)
+{
+	return path ? maxPtr(strrchr(path, '/'), strrchr(path, '\\')) : nullptr;
+}
+
+inline const wchar_t* getLastPathSeparator(const wchar_t* path)
+{
+	return path ? maxPtr(wcsrchr(path, L'/'), wcsrchr(path, L'\\')) : nullptr;
+}
+
+// Returns the whole path when it contains no separator
+inline const char* getFileName(const char* path)
+{
+	const char* lastSeparator = getLastPathSeparator(path);
+	return lastSeparator ? lastSeparator + 1 : path;
+}
+
 inline const char* getExtension(const char* path)
 {
 	const char* lastDot = strrchr(path, '.');
@@ -64,7 +97,7 @@ inline const char* getExtension(const char* path)
 		return nullptr;
 	}
 
-	const char* lastSeparator = maxPtr(strrchr(path, '/'), strrchr(path, '\\'));
+	const char* lastSeparator = getLastPathSeparator(path);
 
 	// Check if the dot is contained in the filename
 	if (lastSeparator && lastDot < lastSeparator)
@@ -84,7 +117,7 @@ inline const wchar_t* getExtension(const wchar_t* path)
 		return nullptr;
 	}
 
-	const wchar_t* lastSeparator = maxPtr(wcsrchr(path, L'/'), wcsrchr(path, L'\\'));
+	const wchar_t* lastSeparator = getLastPathSeparator(path);
 
 	// Check if the dot is contained in the filename
 	if (lastSeparator && lastDot < lastSeparator)