diff --git a/code/ColladaLoader.cpp b/code/ColladaLoader.cpp
index 45dd52710..611e487b0 100644
--- a/code/ColladaLoader.cpp
+++ b/code/ColladaLoader.cpp
@@ -1819,9 +1819,12 @@ void ColladaLoader::ConvertPath (aiString& ss)
 
   // Maxon Cinema Collada Export writes "file:///C:\andsoon" with three slashes...
   // I need to filter it without destroying linux paths starting with "/somewhere"
-  if( ss.data[0] == '/' && isalpha( ss.data[1]) && ss.data[2] == ':' )
-  {
-    ss.length--;
+#if defined( _MSC_VER )
+    if( ss.data[0] == '/' && isalpha( (unsigned char) ss.data[1]) && ss.data[2] == ':' ) {
+#else
+    if (ss.data[ 0 ] == '/' && isalpha( ss.data[ 1 ] ) && ss.data[ 2 ] == ':') {
+#endif
+    --ss.length;
     ::memmove( ss.data, ss.data+1, ss.length);
     ss.data[ss.length] = 0;
   }