diff --git a/src/OneWare.Essentials/Helpers/StudioInstanceChannel.cs b/src/OneWare.Essentials/Helpers/StudioInstanceChannel.cs
index 300df472..10fd05f4 100644
--- a/src/OneWare.Essentials/Helpers/StudioInstanceChannel.cs
+++ b/src/OneWare.Essentials/Helpers/StudioInstanceChannel.cs
@@ -1,4 +1,5 @@
 using System.IO.Pipes;
+using System.Security.Cryptography;
 using System.Text;
 
 namespace OneWare.Essentials.Helpers;
@@ -6,6 +7,8 @@ namespace OneWare.Essentials.Helpers;
 /// <summary>
 /// Per-user single-instance lock and IPC channel of the running OneWare Studio.
 /// Used by the desktop app (lock + server) and by CLI modules or a second instance to talk to it.
+/// A Studio started with its own application data directory (<c>--oneware-appdata-dir</c>, e.g. a portable
+/// copy) gets its own channel, so it neither forwards to nor receives requests from the default instance.
 /// </summary>
 public sealed class StudioInstanceChannel
 {
@@ -33,9 +36,12 @@ public StudioInstanceChannel(string lockFilePath, string pipeName)
     }
 
     /// <summary>
-    /// Channel used by OneWare Studio for the current user.
+    /// Channel of the OneWare Studio that uses the current <c>ONEWARE_APPDATA_DIR</c>
+    /// (set by <c>--oneware-appdata-dir</c>), or the default channel of the current user.
+    /// Read it after the startup arguments were applied.
     /// </summary>
-    public static StudioInstanceChannel Default { get; } = CreateDefault();
+    public static StudioInstanceChannel Default =>
+        ForAppDataDirectory(Environment.GetEnvironmentVariable("ONEWARE_APPDATA_DIR"));
 
     public string LockFilePath { get; }
 
@@ -242,14 +248,29 @@ private NamedPipeServerStream CreateServer()
             PipeTransmissionMode.Byte, PipeOptions.Asynchronous | PipeOptions.CurrentUserOnly);
     }
 
-    private static StudioInstanceChannel CreateDefault()
+    /// <summary>
+    /// Channel of the Studio that stores its application data in <paramref name="appDataDirectory" />.
+    /// <c>null</c> or empty returns the default channel of the current user.
+    /// </summary>
+    public static StudioInstanceChannel ForAppDataDirectory(string? appDataDirectory)
     {
+        var suffix = string.IsNullOrWhiteSpace(appDataDirectory) ? "" : "-" + HashDirectory(appDataDirectory);
         var directory = GetUserRuntimeDirectory();
         var pipeName = OperatingSystem.IsWindows()
-            ? $"oneware-studio-ipc-{SanitizeName(Environment.UserName)}"
-            : Path.Combine(directory, "ipc.sock");
+            ? $"oneware-studio-ipc-{SanitizeName(Environment.UserName)}{suffix}"
+            : Path.Combine(directory, $"ipc{suffix}.sock");
+
+        return new StudioInstanceChannel(Path.Combine(directory, $"oneware-studio{suffix}.lock"), pipeName);
+    }
+
+    private static string HashDirectory(string directory)
+    {
+        var path = Path.TrimEndingDirectorySeparator(Path.GetFullPath(directory));
+        if (OperatingSystem.IsWindows())
+            path = path.ToUpperInvariant();
 
-        return new StudioInstanceChannel(Path.Combine(directory, "oneware-studio.lock"), pipeName);
+        // Short enough for the Unix socket path limit, long enough to keep distinct folders apart.
+        return Convert.ToHexString(SHA256.HashData(Encoding.UTF8.GetBytes(path)))[..16].ToLowerInvariant();
     }
 
     private static string GetUserRuntimeDirectory()
diff --git a/studio/OneWare.Studio.Desktop/Program.cs b/studio/OneWare.Studio.Desktop/Program.cs
index 15522121..799b2261 100644
--- a/studio/OneWare.Studio.Desktop/Program.cs
+++ b/studio/OneWare.Studio.Desktop/Program.cs
@@ -28,12 +28,18 @@ namespace OneWare.Studio.Desktop;
 
 internal abstract class Program
 {
-    private static readonly StudioInstanceChannel InstanceChannel = StudioInstanceChannel.Default;
+    private static StudioInstanceChannel? _instanceChannel;
     private static readonly Queue<string> PendingIpcMessages = new();
     private static FileStream? _lockFileStream;
     private static CancellationTokenSource? _ipcCancellation;
     private static bool _ipcReady;
 
+    /// <summary>
+    /// The channel depends on --oneware-appdata-dir, so it is created after the startup arguments were applied.
+    /// </summary>
+    private static StudioInstanceChannel GetInstanceChannel() =>
+        _instanceChannel ??= StudioInstanceChannel.Default;
+
     public static void ReleaseLock()
     {
         try
@@ -106,7 +112,7 @@ private static bool TryBecomePrimaryInstance()
     {
         try
         {
-            _lockFileStream = InstanceChannel.TryAcquirePrimaryLock();
+            _lockFileStream = GetInstanceChannel().TryAcquirePrimaryLock();
             if (_lockFileStream == null)
             {
                 Console.WriteLine("Another instance is already running.");
@@ -240,7 +246,7 @@ public static int Main(string[] args)
                               ?? Environment.GetEnvironmentVariable("ONEWARE_OPEN_PATH")
                               ?? StudioInstanceChannel.FormatCommand(StudioInstanceChannel.ActivateCommand);
 
-                if (InstanceChannel.SendMessageAsync(message).GetAwaiter().GetResult())
+                if (GetInstanceChannel().SendMessageAsync(message).GetAwaiter().GetResult())
                 {
                     Console.WriteLine("Request forwarded successfully.");
                     return 0;
@@ -253,7 +259,7 @@ public static int Main(string[] args)
             // We are the primary instance - start IPC server
             _ipcCancellation = new CancellationTokenSource();
             var ipcToken = _ipcCancellation.Token;
-            _ = Task.Run(() => InstanceChannel.RunServerAsync(ReceiveIpcMessage,
+            _ = Task.Run(() => GetInstanceChannel().RunServerAsync(ReceiveIpcMessage,
                 ex => Console.WriteLine($"IPC Server error: {ex.Message}"), ipcToken));
 
             var appBuilder = BuildAvaloniaApp();
diff --git a/tests/OneWare.Essentials.UnitTests/StudioInstanceChannelTests.cs b/tests/OneWare.Essentials.UnitTests/StudioInstanceChannelTests.cs
index cb6d9ccb..fc95a178 100644
--- a/tests/OneWare.Essentials.UnitTests/StudioInstanceChannelTests.cs
+++ b/tests/OneWare.Essentials.UnitTests/StudioInstanceChannelTests.cs
@@ -59,6 +59,39 @@ public void TryParseCommand_RejectsNonCommands(string message)
         Assert.False(StudioInstanceChannel.TryParseCommand(message, out _, out _));
     }
 
+    [Fact]
+    public void ForAppDataDirectory_WithoutDirectory_ReturnsUserChannel()
+    {
+        var channel = StudioInstanceChannel.ForAppDataDirectory(null);
+
+        Assert.Equal("oneware-studio.lock", Path.GetFileName(channel.LockFilePath));
+        Assert.Equal(channel.PipeName, StudioInstanceChannel.ForAppDataDirectory(" ").PipeName);
+    }
+
+    [Fact]
+    public void ForAppDataDirectory_SeparatesDirectories()
+    {
+        var user = StudioInstanceChannel.ForAppDataDirectory(null);
+        var first = StudioInstanceChannel.ForAppDataDirectory(Path.Combine(_directory, "a"));
+        var second = StudioInstanceChannel.ForAppDataDirectory(Path.Combine(_directory, "b"));
+
+        Assert.NotEqual(user.LockFilePath, first.LockFilePath);
+        Assert.NotEqual(user.PipeName, first.PipeName);
+        Assert.NotEqual(first.LockFilePath, second.LockFilePath);
+        Assert.NotEqual(first.PipeName, second.PipeName);
+    }
+
+    [Fact]
+    public void ForAppDataDirectory_IgnoresTrailingSeparator()
+    {
+        var path = Path.Combine(_directory, "portable");
+        var first = StudioInstanceChannel.ForAppDataDirectory(path);
+        var second = StudioInstanceChannel.ForAppDataDirectory(path + Path.DirectorySeparatorChar);
+
+        Assert.Equal(first.LockFilePath, second.LockFilePath);
+        Assert.Equal(first.PipeName, second.PipeName);
+    }
+
     [Fact]
     public void Lock_IsDetectedWhileHeldAndReleasedOnDispose()
     {