1diff --git a/src/Runner.Common/HostContext.cs b/src/Runner.Common/HostContext.cs
2index d4ea48c..2ec8455 100644
3--- a/src/Runner.Common/HostContext.cs
4+++ b/src/Runner.Common/HostContext.cs
5@@ -220,12 +220,13 @@ namespace GitHub.Runner.Common
6
7 case WellKnownDirectory.Externals:
8 path = Path.Combine(
9- GetDirectory(WellKnownDirectory.Root),
10+ new DirectoryInfo(GetDirectory(WellKnownDirectory.Bin)).Parent.FullName,
11 Constants.Path.ExternalsDirectory);
12 break;
13
14 case WellKnownDirectory.Root:
15- path = new DirectoryInfo(GetDirectory(WellKnownDirectory.Bin)).Parent.FullName;
16+ path = Environment.GetEnvironmentVariable("RUNNER_ROOT")
17+ ?? new DirectoryInfo(GetDirectory(WellKnownDirectory.Bin)).Parent.FullName;
18 break;
19
20 case WellKnownDirectory.Temp: