diff --git a/src/Agent.Worker/ContainerOperationProvider.cs b/src/Agent.Worker/ContainerOperationProvider.cs
index bddba38ce0..7d225c7587 100644
--- a/src/Agent.Worker/ContainerOperationProvider.cs
+++ b/src/Agent.Worker/ContainerOperationProvider.cs
@@ -177,7 +177,13 @@ public async Task StartContainerAsync(IExecutionContext executionContext, object
                 container.MountVolumes.Add(new MountVolume(HostContext.GetDirectory(WellKnownDirectory.Work), container.TranslateToContainerPath(HostContext.GetDirectory(WellKnownDirectory.Work))));
                 container.MountVolumes.Add(new MountVolume(HostContext.GetDirectory(WellKnownDirectory.Tools), container.TranslateToContainerPath(HostContext.GetDirectory(WellKnownDirectory.Tools))));
 #else
-                string workingDirectory = Path.GetDirectoryName(executionContext.Variables.Get(Constants.Variables.System.DefaultWorkingDirectory).TrimEnd(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar));
+                string defaultWorkingDirectory = executionContext.Variables.Get(Constants.Variables.System.DefaultWorkingDirectory);
+                if (string.IsNullOrEmpty(defaultWorkingDirectory))
+                {
+                    throw new NotSupportedException(StringUtil.Loc("ContainerJobRequireSystemDefaultWorkDir"));
+                }
+
+                string workingDirectory = Path.GetDirectoryName(defaultWorkingDirectory.TrimEnd(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar));
                 container.MountVolumes.Add(new MountVolume(container.TranslateToHostPath(workingDirectory), workingDirectory));
                 container.MountVolumes.Add(new MountVolume(HostContext.GetDirectory(WellKnownDirectory.Temp), container.TranslateToContainerPath(HostContext.GetDirectory(WellKnownDirectory.Temp))));
                 container.MountVolumes.Add(new MountVolume(HostContext.GetDirectory(WellKnownDirectory.Tools), container.TranslateToContainerPath(HostContext.GetDirectory(WellKnownDirectory.Tools))));
diff --git a/src/Misc/layoutbin/en-US/strings.json b/src/Misc/layoutbin/en-US/strings.json
index a4a74e100e..45fcf40b8c 100644
--- a/src/Misc/layoutbin/en-US/strings.json
+++ b/src/Misc/layoutbin/en-US/strings.json
@@ -206,6 +206,7 @@
   "ConnectingToServer": "Connecting to server ...",
   "ConnectSectionHeader": "Connect",
   "ConnectToServer": "Connecting to the server.",
+  "ContainerJobRequireSystemDefaultWorkDir": "System.DefaultWorkingDirectory is required for running a container job.",
   "ContainerWindowsVersionRequirement": "Container feature requires Windows Server 1803 or higher. Please reference documentation (https://go.microsoft.com/fwlink/?linkid=875268)",
   "CouldNotRemoveService": "Could not delete service '{0}'",
   "CreateUserWithSameUIDInsideContainer": "Try create an user with UID '{0}' inside the container.",