diff --git a/lib/index.js b/lib/index.js
index 2e675b2..8c98ea6 100755
--- a/lib/index.js
+++ b/lib/index.js
@@ -80,7 +80,11 @@ internals.Assertion.prototype.assert = function (result, verb, actual, expected)
         this._ref instanceof Error) {
 
         const original = this._ref;
-        original.at = internals.at(this._ref);
+        const at = internals.at(this._ref);
+
+        if (at !== undefined) {
+            original.at = at;
+        }
 
         throw original;
     }
@@ -432,12 +436,14 @@ internals.type = function (value) {
 internals.at = function (error) {
 
     error = error || new Error();
-    const at = error.stack.replace(error.toString(), '').split('\n').slice(1).filter(internals.filterLocal)[0].match(/^\s*at \(?(.+)\:(\d+)\:(\d+)\)?$/);
-    return {
+    const stack = typeof error.stack === 'string' ? error.stack : '';
+    const frame = stack.replace(error.toString(), '').split('\n').slice(1).filter(internals.filterLocal)[0] || '';
+    const at = frame.match(/^\s*at \(?(.+)\:(\d+)\:(\d+)\)?$/);
+    return Array.isArray(at) ? {
         filename: at[1],
         line: at[2],
         column: at[3]
-    };
+    } : undefined;
 };
 
 
diff --git a/test/index.js b/test/index.js
index 8bd7ca3..4624e4f 100755
--- a/test/index.js
+++ b/test/index.js
@@ -1039,6 +1039,23 @@ describe('expect()', () => {
                 Hoek.assert(exception.message === 'some message', exception);
                 done();
             });
+
+            it('validates assertion (error with incomplete stack)', (done) => {
+
+                let exception = false;
+                try {
+                    const err = new Error('foo');
+                    err.stack = undefined;
+                    Code.expect(err).to.not.exist();
+                }
+                catch (err) {
+                    exception = err;
+                }
+
+                Hoek.assert(exception.message === 'foo', exception);
+                Hoek.assert(exception.at === undefined, exception);
+                done();
+            });
         });
 
         describe('empty()', () => {