diff --git a/src/Microsoft.AspNetCore.Server.IntegrationTesting/Deployers/IISExpressDeployer.cs b/src/Microsoft.AspNetCore.Server.IntegrationTesting/Deployers/IISExpressDeployer.cs
index de1725b8f7..44fcf41537 100644
--- a/src/Microsoft.AspNetCore.Server.IntegrationTesting/Deployers/IISExpressDeployer.cs
+++ b/src/Microsoft.AspNetCore.Server.IntegrationTesting/Deployers/IISExpressDeployer.cs
@@ -111,7 +111,7 @@ namespace Microsoft.AspNetCore.Server.IntegrationTesting
                             string ancmPath;
                             // We need to pick the bitness based the OS / IIS Express, not the application.
                             // We'll eventually add support for choosing which IIS Express bitness to run: https://github.com/aspnet/Hosting/issues/880
-                            var ancmFile = Is64BitHost ? "\x64\aspnetcore.dll" : "\x86\aspnetcore.dll";
+                            var ancmFile = Is64BitHost ? @"x64\aspnetcore.dll" : @"x86\aspnetcore.dll";
                             // Bin deployed by Microsoft.AspNetCore.AspNetCoreModule.nupkg
                             if (DeploymentParameters.RuntimeFlavor == RuntimeFlavor.CoreClr
                                 && DeploymentParameters.ApplicationType == ApplicationType.Portable)