diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index 6dd593c7fee..9e4d5cd1da4 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -4019,7 +4019,8 @@ module ts {
 
         function processReferencedFiles(file: SourceFile, basePath: string) {
             forEach(file.referencedFiles, ref => {
-                processSourceFile(normalizePath(combinePaths(basePath, ref.filename)), /* isDefaultLib */ false, file, ref.pos, ref.end);
+                var referencedFilename = isRootedDiskPath(ref.filename) ? ref.filename : combinePaths(basePath, ref.filename);
+                processSourceFile(normalizePath(referencedFilename), /* isDefaultLib */ false, file, ref.pos, ref.end);
             });
         }
 
diff --git a/src/services/services.ts b/src/services/services.ts
index a35c1213956..ced52fd69c3 100644
--- a/src/services/services.ts
+++ b/src/services/services.ts
@@ -2573,7 +2573,8 @@ module ts {
             /// Triple slash reference comments
             var comment = forEach(sourceFile.referencedFiles, r => (r.pos <= position && position < r.end) ? r : undefined);
             if (comment) {
-                var targetFilename = normalizePath(combinePaths(getDirectoryPath(filename), comment.filename));
+                var targetFilename = isRootedDiskPath(comment.filename) ? comment.filename : combinePaths(getDirectoryPath(filename), comment.filename);
+                targetFilename = normalizePath(targetFilename);
                 if (program.getSourceFile(targetFilename)) {
                     return [{
                         fileName: targetFilename,