diff --git a/Source/Core/DiscIO/FileMonitor.cpp b/Source/Core/DiscIO/FileMonitor.cpp
index ce8799b227..723a02eb2c 100644
--- a/Source/Core/DiscIO/FileMonitor.cpp
+++ b/Source/Core/DiscIO/FileMonitor.cpp
@@ -38,7 +38,7 @@ bool IsSoundFile(const std::string& filename)
 	SplitPath(filename, nullptr, nullptr, &extension);
 	std::transform(extension.begin(), extension.end(), extension.begin(), ::tolower);
 
-	std::unordered_set<std::string> extensions = {
+	static std::unordered_set<std::string> extensions = {
 		".adp",   // 1080 Avalanche, Crash Bandicoot, etc.
 		".adx",   // Sonic Adventure 2 Battle, etc.
 		".afc",   // Zelda WW