diff --git a/src/Xamarin.Android.Tools.AndroidSdk/Sdks/AndroidSdkBase.cs b/src/Xamarin.Android.Tools.AndroidSdk/Sdks/AndroidSdkBase.cs
index 59fc390..b39b75f 100644
--- a/src/Xamarin.Android.Tools.AndroidSdk/Sdks/AndroidSdkBase.cs
+++ b/src/Xamarin.Android.Tools.AndroidSdk/Sdks/AndroidSdkBase.cs
@@ -152,7 +152,7 @@ protected virtual IEnumerable<string> GetAllAvailableAndroidNdks ()
 			// Look in PATH
 			foreach (var ndkStack in ProcessUtils.FindExecutablesInPath (NdkStack)) {
 				var ndkDir  = Path.GetDirectoryName (ndkStack);
-				if (ndkDir == null)
+				if (string.IsNullOrEmpty (ndkDir))
 					continue;
 				yield return ndkDir;
 			}
@@ -161,12 +161,19 @@ protected virtual IEnumerable<string> GetAllAvailableAndroidNdks ()
 			foreach (var sdk in GetAllAvailableAndroidSdks ()) {
 				if (sdk == AndroidSdkPath)
 					continue;
-				yield return FindBestNDK (sdk);
+				var ndkDir = FindBestNDK (sdk);
+				if (string.IsNullOrEmpty (ndkDir))
+					continue;
+				yield return ndkDir;
 			}
 		}
 
 		string FindBestNDK (string androidSdkPath)
 		{
+			if (!Directory.Exists (androidSdkPath)) {
+				return String.Empty;
+			}
+
 			var ndkInstances = new SortedDictionary<Version, string> (Comparer<Version>.Create ((Version l, Version r) => r.CompareTo (l)));
 
 			foreach (string ndkPath in Directory.EnumerateDirectories (androidSdkPath, "ndk*", SearchOption.TopDirectoryOnly)) {
diff --git a/tests/Xamarin.Android.Tools.AndroidSdk-Tests/AndroidSdkInfoTests.cs b/tests/Xamarin.Android.Tools.AndroidSdk-Tests/AndroidSdkInfoTests.cs
index 7efcaa2..54dc353 100644
--- a/tests/Xamarin.Android.Tools.AndroidSdk-Tests/AndroidSdkInfoTests.cs
+++ b/tests/Xamarin.Android.Tools.AndroidSdk-Tests/AndroidSdkInfoTests.cs
@@ -146,6 +146,28 @@ public void Ndk_PathInSdk()
 			}
 		}
 
+		[Test]
+		public void Ndk_AndroidSdkDoesNotExist ()
+		{
+			CreateSdks (out string root, out string jdk, out string ndk, out string sdk);
+
+			Action<TraceLevel, string> logger = (level, message) => {
+				Console.WriteLine ($"[{level}] {message}");
+				if (level == TraceLevel.Error)
+					Assert.Fail (message);
+			};
+
+			var oldAndroidHome = Environment.GetEnvironmentVariable ("ANDROID_HOME");
+			try {
+				Environment.SetEnvironmentVariable ("ANDROID_HOME", "/i/dont/exist");
+				// Check that this doesn't throw
+				new AndroidSdkInfo (logger, androidSdkPath: sdk, androidNdkPath: null, javaSdkPath: jdk);
+			} finally {
+				Environment.SetEnvironmentVariable ("ANDROID_HOME", oldAndroidHome);
+				Directory.Delete (root, recursive: true);
+			}
+		}
+
 		[Test]
 		public void Constructor_SetValuesFromPath ()
 		{