diff --git a/source/Calamari.Tests/ArgoCD/Git/AuthenticatingRepositoryFactoryTests.cs b/source/Calamari.Tests/ArgoCD/Git/AuthenticatingRepositoryFactoryTests.cs
index 3d4593717..5d559298f 100644
--- a/source/Calamari.Tests/ArgoCD/Git/AuthenticatingRepositoryFactoryTests.cs
+++ b/source/Calamari.Tests/ArgoCD/Git/AuthenticatingRepositoryFactoryTests.cs
@@ -81,6 +81,8 @@ public void AnonymousCloneWhenNoCredentialsMatch()
     public class SshUrlTests : AuthenticatingRepositoryFactoryTestBase
     {
         [Test]
+        // SSH not currently functional on Windows
+        [Category(TestCategory.CompatibleOS.OnlyNixOrMac)]
         public void SshCredentialBranch_IsSelectedAndDispatchesSshKeyGitConnection()
         {
             // Use an ssh:// URL so the new strict validation allows it, and mock the factory
@@ -108,6 +110,8 @@ public void HttpsCredentialTakesPriorityOverSshWhenBothMatchAnSshUrl()
         }
 
         [Test]
+        // SSH not currently functional on Windows
+        [Category(TestCategory.CompatibleOS.OnlyNixOrMac)]
         public void KnownHostsFromDtoAreCarriedOntoSshKeyGitConnection()
         {
             const string sshUrl = "ssh://git@github.com/org/repo.git";
diff --git a/source/Calamari.Tests/ArgoCD/Git/RepositoryFactoryTests.cs b/source/Calamari.Tests/ArgoCD/Git/RepositoryFactoryTests.cs
index d9103a546..f52231a15 100644
--- a/source/Calamari.Tests/ArgoCD/Git/RepositoryFactoryTests.cs
+++ b/source/Calamari.Tests/ArgoCD/Git/RepositoryFactoryTests.cs
@@ -96,6 +96,8 @@ public void CanCloneAnExistingRepositoryAtHEADAndAssociatedFiles()
         }
 
         [Test]
+        // SSH not currently functional on Windows
+        [Category(TestCategory.CompatibleOS.OnlyNixOrMac)]
         public void CloningSshKeyGitConnectionDoesNotResolveAPullRequestClientAndLogsVerboseMessage()
         {
             var filename = "sshTest.txt";
diff --git a/source/Calamari/ArgoCD/Git/RepositoryFactory.cs b/source/Calamari/ArgoCD/Git/RepositoryFactory.cs
index 6b70ec16b..771c9b83b 100644
--- a/source/Calamari/ArgoCD/Git/RepositoryFactory.cs
+++ b/source/Calamari/ArgoCD/Git/RepositoryFactory.cs
@@ -1,10 +1,10 @@
 using System;
 using System.IO;
 using System.Linq;
-using System.Text;
 using System.Threading;
 using Calamari.ArgoCD.Git.PullRequests;
 using Calamari.Common.Commands;
+using Calamari.Common.Plumbing;
 using Calamari.Common.Plumbing.Extensions;
 using Calamari.Common.Plumbing.FileSystem;
 using Calamari.Common.Plumbing.Logging;
@@ -48,6 +48,8 @@ public RepositoryFactory(ILog log, ICalamariFileSystem fileSystem, string reposi
 
         public RepositoryWrapper CloneRepository(string repositoryName, IGitConnection gitConnection)
         {
+            WindowsSshKeys.AssertSupported(gitConnection);
+
             var repositoryPath = Path.Combine(repositoryParentDirectory, repositoryName);
             fileSystem.CreateDirectory(repositoryPath);
 
diff --git a/source/Calamari/ArgoCD/Git/WindowsSshKeys.cs b/source/Calamari/ArgoCD/Git/WindowsSshKeys.cs
new file mode 100644
index 000000000..e84bb5208
--- /dev/null
+++ b/source/Calamari/ArgoCD/Git/WindowsSshKeys.cs
@@ -0,0 +1,20 @@
+using System;
+using Calamari.Common.Plumbing;
+using NuGet.Commands;
+
+namespace Calamari.ArgoCD.Git;
+
+// Our fork LibGit2Sharp uses WinCNG for it's SSH support, and WinCNG does not support some keys.
+// This first implementation blocks on all as we want to get the feature out for Linux first and
+// we'll come back to attempt to handle it more gracefully at a later date.
+public class WindowsSshKeys
+{
+    public static void AssertSupported(IGitConnection? connection)
+    {
+        if (!CalamariEnvironment.IsRunningOnWindows) return;
+        if (connection is not SshKeyGitConnection) return;
+
+        throw new CommandException(
+            "SSH credentials are not currently supported for Git operations running on Windows. Use HTTPS credentials (username + password or PAT) instead or run the deployment on a Linux worker.");
+    }
+}
\ No newline at end of file