diff --git a/extern/igfd/ImGuiFileDialog.cpp b/extern/igfd/ImGuiFileDialog.cpp
index a7c1c2b89..b53cdf7d6 100644
--- a/extern/igfd/ImGuiFileDialog.cpp
+++ b/extern/igfd/ImGuiFileDialog.cpp
@@ -3859,7 +3859,7 @@ namespace IGFD
       }
     }
 #endif
-    for (const char* i=n; *i; i++) {
+    for (const unsigned char* i=(const unsigned char*)n; *i; i++) {
 #ifdef _WIN32
       if (*i<32) {
         return 3;