diff --git a/src/services/utilities.ts b/src/services/utilities.ts
index 8dcd06f5621..88e3601b610 100644
--- a/src/services/utilities.ts
+++ b/src/services/utilities.ts
@@ -224,7 +224,10 @@ module ts {
             return nodeHasTokens((<ExpressionStatement>n).expression);
         }
 
-        if (n.kind === SyntaxKind.EndOfFileToken || n.kind === SyntaxKind.OmittedExpression || n.kind === SyntaxKind.Missing) {
+        if (n.kind === SyntaxKind.EndOfFileToken ||
+            n.kind === SyntaxKind.OmittedExpression ||
+            n.kind === SyntaxKind.Missing ||
+            n.kind === SyntaxKind.Unknown) {
             return false;
         }
 
diff --git a/tests/cases/fourslash/completionAfterAtChar.ts b/tests/cases/fourslash/completionAfterAtChar.ts
new file mode 100644
index 00000000000..4f3581cd483
--- /dev/null
+++ b/tests/cases/fourslash/completionAfterAtChar.ts
@@ -0,0 +1,6 @@
+/// <reference path='fourslash.ts'/>
+
+////@a/**/
+
+goTo.marker();
+verify.not.completionListIsEmpty();
\ No newline at end of file