diff --git a/src/NzbDrone.Api/RootFolders/RootFolderModule.cs b/src/NzbDrone.Api/RootFolders/RootFolderModule.cs
index 9c9fed0d4..a4c0f892b 100644
--- a/src/NzbDrone.Api/RootFolders/RootFolderModule.cs
+++ b/src/NzbDrone.Api/RootFolders/RootFolderModule.cs
@@ -16,7 +16,8 @@ public RootFolderModule(IRootFolderService rootFolderService,
                                 RootFolderValidator rootFolderValidator,
                                 PathExistsValidator pathExistsValidator,
                                 DroneFactoryValidator droneFactoryValidator,
-                                MappedNetworkDriveValidator mappedNetworkDriveValidator)
+                                MappedNetworkDriveValidator mappedNetworkDriveValidator,
+                                StartupFolderValidator startupFolderValidator)
             : base(signalRBroadcaster)
         {
             _rootFolderService = rootFolderService;
@@ -32,6 +33,7 @@ public RootFolderModule(IRootFolderService rootFolderService,
                            .SetValidator(rootFolderValidator)
                            .SetValidator(droneFactoryValidator)
                            .SetValidator(mappedNetworkDriveValidator)
+                           .SetValidator(startupFolderValidator)
                            .SetValidator(pathExistsValidator);
         }
 
diff --git a/src/NzbDrone.Core/NzbDrone.Core.csproj b/src/NzbDrone.Core/NzbDrone.Core.csproj
index ae947c2f4..7369f3002 100644
--- a/src/NzbDrone.Core/NzbDrone.Core.csproj
+++ b/src/NzbDrone.Core/NzbDrone.Core.csproj
@@ -1032,6 +1032,7 @@
     <Compile Include="Validation\Paths\DroneFactoryValidator.cs" />
     <Compile Include="Validation\Paths\PathExistsValidator.cs" />
     <Compile Include="Validation\Paths\PathValidator.cs" />
+    <Compile Include="Validation\Paths\StartupFolderValidator.cs" />
     <Compile Include="Validation\Paths\RootFolderValidator.cs" />
     <Compile Include="Validation\Paths\SeriesAncestorValidator.cs" />
     <Compile Include="Validation\Paths\SeriesExistsValidator.cs" />
diff --git a/src/NzbDrone.Core/Validation/Paths/StartupFolderValidator.cs b/src/NzbDrone.Core/Validation/Paths/StartupFolderValidator.cs
new file mode 100644
index 000000000..89fd0893e
--- /dev/null
+++ b/src/NzbDrone.Core/Validation/Paths/StartupFolderValidator.cs
@@ -0,0 +1,25 @@
+using FluentValidation.Validators;
+using NzbDrone.Common.EnvironmentInfo;
+using NzbDrone.Common.Extensions;
+
+namespace NzbDrone.Core.Validation.Paths
+{
+    public class StartupFolderValidator : PropertyValidator
+    {
+        private readonly IAppFolderInfo _appFolderInfo;
+        
+
+        public StartupFolderValidator(IAppFolderInfo appFolderInfo)
+            : base("Path cannot be an ancestor of the start up folder")
+        {
+            _appFolderInfo = appFolderInfo;
+        }
+
+        protected override bool IsValid(PropertyValidatorContext context)
+        {
+            if (context.PropertyValue == null) return true;
+
+            return !_appFolderInfo.StartUpFolder.IsParentPath(context.PropertyValue.ToString());
+        }
+    }
+}
\ No newline at end of file