Client rename residuals: lmxopcua-cli → otopcua-cli + LmxOpcUaClient → OtOpcUaClient with migration shim. Closes task #208 (the executable-name + LocalAppData-folder slice that was called out in Client.CLI.md / Client.UI.md as a deliberately-deferred residual of the Phase 0 rename). Six source references flipped to the canonical OtOpcUaClient spelling: Program.cs CliFx executable name + description (lmxopcua-cli → otopcua-cli), DefaultApplicationConfigurationFactory.cs ApplicationName + ApplicationUri (LmxOpcUaClient + urn:localhost:LmxOpcUaClient → OtOpcUaClient + urn:localhost:OtOpcUaClient), OpcUaClientService.CreateSessionAsync session-name arg, ConnectionSettings.CertificateStorePath default, MainWindowViewModel.CertificateStorePath default, JsonSettingsService.SettingsDir. Two consuming tests (ConnectionSettingsTests + MainWindowViewModelTests) updated to assert the new canonical name. New ClientStoragePaths static helper at src/ZB.MOM.WW.OtOpcUa.Client.Shared/ClientStoragePaths.cs is the migration shim — single entry point for the PKI root + pki subpath, runs a one-shot legacy-folder probe on first resolution: if {LocalAppData}/LmxOpcUaClient/ exists + {LocalAppData}/OtOpcUaClient/ does not, Directory.Move renames it in place (atomic on NTFS within the same volume) so trusted server certs + saved connection settings persist across the rename without operator action. Idempotent per-process via a Lock-guarded _migrationChecked flag so repeated CertificateStorePath getter calls on the hot path pay no IO cost beyond the first. Fresh-install path (neither folder exists) + already-migrated path (only canonical exists) + manual-override path (both exist — developer has set up something explicit) are all no-ops that leave state alone. IOException on the Directory.Move is swallowed + logged as a false return so a concurrent peer process losing the race doesn't crash the consumer; the losing process falls back to whatever state exists. Five new ClientStoragePathsTests assert: GetRoot ends with canonical name under LocalAppData, GetPkiPath nests pki under root, CanonicalFolderName is OtOpcUaClient, LegacyFolderName is LmxOpcUaClient (the migration contract — a typo here would leak the legacy folder past the shim), repeat invocation returns false after first-touch arms the in-process guard. Doc-side residual-explanation notes in docs/Client.CLI.md + docs/Client.UI.md are dropped now that the rename is real; replaced with a short "pre-#208 dev boxes migrate automatically on first launch" note that points at ClientStoragePaths. Sample CLI invocations in Client.CLI.md updated via sed from lmxopcua-cli to otopcua-cli across every command block (14 replacements). Pre-existing staleness in SubscribeCommandTests.Execute_PrintsSubscriptionMessage surfaced during the test run — the CLI's subscribe command has long since switched to an aggregate "Subscribed to {count}/{total} nodes (interval: ...)" output format but the test still asserted the original single-node form. Updated the assertion to match current output + added a comment explaining the change; this is unrelated to the rename but was blocking a green Client.CLI.Tests run. Full solution build 0 errors; Client.Shared.Tests 136/136 + 5 new shim tests passing; Client.UI.Tests 98/98; Client.CLI.Tests 52/52 (was 51/52 before the subscribe-test fix). No Admin/Core/Server changes — this touches only the client layer.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -87,13 +87,14 @@ The server supports non-transparent warm/hot redundancy via the `Redundancy` sec
 
 ## LDAP Authentication
 
-The server uses LDAP-based user authentication via the `Authentication.Ldap` section in `appsettings.json`. When enabled, credentials are validated by LDAP bind against a GLAuth server (installed at `C:\publish\glauth\`), and LDAP group membership maps to OPC UA permissions: `ReadOnly` (browse/read), `WriteOperate` (write FreeAccess/Operate attributes), `WriteTune` (write Tune attributes), `WriteConfigure` (write Configure attributes), `AlarmAck` (alarm acknowledgment). `LdapAuthenticationProvider` implements both `IUserAuthenticationProvider` and `IRoleProvider`. See `docs/Security.md` for the full guide and `C:\publish\glauth\auth.md` for LDAP user/group reference.
+The server uses LDAP-based user authentication via the `Authentication.Ldap` section in `appsettings.json`. When enabled, credentials are validated by LDAP bind against a GLAuth server (installed at `C:\publish\glauth\`), and LDAP group membership maps to OPC UA permissions: `ReadOnly` (browse/read), `WriteOperate` (write FreeAccess/Operate attributes), `WriteTune` (write Tune attributes), `WriteConfigure` (write Configure attributes), `AlarmAck` (alarm acknowledgment). `LdapUserAuthenticator` (`src/ZB.MOM.WW.OtOpcUa.Server/Security/LdapUserAuthenticator.cs`) implements `IUserAuthenticator`. See `docs/Security.md` for the full guide and `C:\publish\glauth\auth.md` for LDAP user/group reference.
 
 ## Library Preferences
 
 - **Logging**: Serilog with rolling daily file sink
 - **Unit tests**: xUnit + Shouldly for assertions
-- **Service hosting**: TopShelf (Windows service install/uninstall/run as console)
+- **Service hosting (Server, Admin)**: .NET generic host with `AddWindowsService` (decision #30 — replaced TopShelf in v2; see `src/ZB.MOM.WW.OtOpcUa.Server/OpcUaServerService.cs`)
+- **Service hosting (Galaxy.Host)**: plain console app wrapped by NSSM (`.NET Framework 4.8 x86` — required by MXAccess COM bitness)
 - **OPC UA**: OPC Foundation UA .NET Standard stack (https://github.com/opcfoundation/ua-.netstandard) — NuGet: `OPCFoundation.NetStandard.Opc.Ua.Server`
 
 ## OPC UA .NET Standard Documentation

docs/Client.CLI.md

@@ -14,7 +14,7 @@ dotnet build
 dotnet run -- <command> [options]
 ```
 
-The executable name is still `lmxopcua-cli` — a residual from the pre-v2 rename (`Program.cs:SetExecutableName`). Scripts + operator muscle memory depend on the name; flipping it to `otopcua-cli` is a follow-up that also needs to move the client-side PKI store folder (<code>{LocalAppData}/LmxOpcUaClient/pki/</code> — used by the shared client for its application certificate) so trust relationships survive the rename.
+The executable name is `otopcua-cli`. Dev boxes carrying a pre-task-#208 install may still have the legacy `{LocalAppData}/LmxOpcUaClient/` folder on disk; on first launch of any post-#208 CLI or UI build, `ClientStoragePaths` (`src/ZB.MOM.WW.OtOpcUa.Client.Shared/ClientStoragePaths.cs`) migrates it to `{LocalAppData}/OtOpcUaClient/` automatically so trusted certificates + saved settings survive the rename.
 
 ## Architecture
 
@@ -46,7 +46,7 @@ All commands accept these options:
 When `-U` and `-P` are provided, the shared service passes a `UserIdentity(username, password)` to the OPC UA session. Without credentials, anonymous identity is used.
 
 ```bash
-lmxopcua-cli write -u opc.tcp://localhost:4840 -n "ns=2;s=MyNode" -v 42 -U operator -P op123
+otopcua-cli write -u opc.tcp://localhost:4840 -n "ns=2;s=MyNode" -v 42 -U operator -P op123
 ```
 
 ### Failover
@@ -54,20 +54,20 @@ lmxopcua-cli write -u opc.tcp://localhost:4840 -n "ns=2;s=MyNode" -v 42 -U opera
 When `-F` is provided, the shared service tries the primary URL first, then each failover URL in order. For long-running commands (`subscribe`, `alarms`), the service monitors the session via keep-alive and automatically reconnects to the next available server on failure.
 
 ```bash
-lmxopcua-cli connect -u opc.tcp://localhost:4840/OtOpcUa -F opc.tcp://localhost:4841/OtOpcUa
+otopcua-cli connect -u opc.tcp://localhost:4840/OtOpcUa -F opc.tcp://localhost:4841/OtOpcUa
 ```
 
 ### Transport Security
 
 When `sign` or `encrypt` is specified, the shared service:
 
-1. Ensures a client application certificate exists under `{LocalAppData}/LmxOpcUaClient/pki/` (auto-created if missing)
+1. Ensures a client application certificate exists under `{LocalAppData}/OtOpcUaClient/pki/` (auto-created if missing; pre-rename `LmxOpcUaClient/` is migrated in place on first launch)
 2. Discovers server endpoints and selects one matching the requested security mode
 3. Prefers `Basic256Sha256` when multiple matching endpoints exist
 4. Fails with a clear error if no matching endpoint is found
 
 ```bash
-lmxopcua-cli browse -u opc.tcp://localhost:4840/OtOpcUa -S encrypt -U admin -P secret -r -d 2
+otopcua-cli browse -u opc.tcp://localhost:4840/OtOpcUa -S encrypt -U admin -P secret -r -d 2
 ```
 
 ### Verbose Logging
@@ -81,7 +81,7 @@ The `--verbose` flag switches Serilog output from `Warning` to `Debug` level, sh
 Tests connectivity to an OPC UA server. Creates a session, prints connection metadata, and disconnects.
 
 ```bash
-lmxopcua-cli connect -u opc.tcp://localhost:4840/OtOpcUa -U admin -P admin123
+otopcua-cli connect -u opc.tcp://localhost:4840/OtOpcUa -U admin -P admin123
 ```
 
 Output:
@@ -99,7 +99,7 @@ Connection successful.
 Reads the current value of a single node and prints the value, status code, and timestamps.
 
 ```bash
-lmxopcua-cli read -u opc.tcp://localhost:4840/OtOpcUa -n "ns=3;s=DEV.ScanState" -U admin -P admin123
+otopcua-cli read -u opc.tcp://localhost:4840/OtOpcUa -n "ns=3;s=DEV.ScanState" -U admin -P admin123
 ```
 
 | Flag | Description |
@@ -121,7 +121,7 @@ Server Time: 2026-03-30T19:58:38.0971257Z
 Writes a value to a node. The shared service reads the current value first to determine the target data type, then converts the supplied string value using `ValueConverter.ConvertValue()`.
 
 ```bash
-lmxopcua-cli write -u opc.tcp://localhost:4840 -n "ns=2;s=MyNode" -v 42
+otopcua-cli write -u opc.tcp://localhost:4840 -n "ns=2;s=MyNode" -v 42
 ```
 
 | Flag | Description |
@@ -135,10 +135,10 @@ Browses the OPC UA address space starting from the Objects folder or a specified
 
 ```bash
 # Browse top-level Objects folder
-lmxopcua-cli browse -u opc.tcp://localhost:4840/OtOpcUa -U admin -P admin123
+otopcua-cli browse -u opc.tcp://localhost:4840/OtOpcUa -U admin -P admin123
 
 # Browse a specific node recursively to depth 3
-lmxopcua-cli browse -u opc.tcp://localhost:4840/OtOpcUa -U admin -P admin123 -r -d 3 -n "ns=3;s=ZB"
+otopcua-cli browse -u opc.tcp://localhost:4840/OtOpcUa -U admin -P admin123 -r -d 3 -n "ns=3;s=ZB"
 ```
 
 | Flag | Description |
@@ -152,7 +152,7 @@ lmxopcua-cli browse -u opc.tcp://localhost:4840/OtOpcUa -U admin -P admin123 -r
 Monitors a node for value changes using OPC UA subscriptions. Prints each data change notification with timestamp, value, and status code. Runs until Ctrl+C, then unsubscribes and disconnects cleanly.
 
 ```bash
-lmxopcua-cli subscribe -u opc.tcp://localhost:4840 -n "ns=2;s=MyNode" -i 500
+otopcua-cli subscribe -u opc.tcp://localhost:4840 -n "ns=2;s=MyNode" -i 500
 ```
 
 | Flag | Description |
@@ -166,12 +166,12 @@ Reads historical data from a node. Supports raw history reads and aggregate (pro
 
 ```bash
 # Raw history
-lmxopcua-cli historyread -u opc.tcp://localhost:4840/OtOpcUa \
+otopcua-cli historyread -u opc.tcp://localhost:4840/OtOpcUa \
   -n "ns=1;s=TestMachine_001.TestHistoryValue" \
   --start "2026-03-25" --end "2026-03-30"
 
 # Aggregate: 1-hour average
-lmxopcua-cli historyread -u opc.tcp://localhost:4840/OtOpcUa \
+otopcua-cli historyread -u opc.tcp://localhost:4840/OtOpcUa \
   -n "ns=1;s=TestMachine_001.TestHistoryValue" \
   --start "2026-03-25" --end "2026-03-30" \
   --aggregate Average --interval 3600000
@@ -203,10 +203,10 @@ Subscribes to alarm events on a node. Prints structured alarm output including s
 
 ```bash
 # Subscribe to alarm events on the Server node
-lmxopcua-cli alarms -u opc.tcp://localhost:4840/OtOpcUa
+otopcua-cli alarms -u opc.tcp://localhost:4840/OtOpcUa
 
 # Subscribe to a specific source node with condition refresh
-lmxopcua-cli alarms -u opc.tcp://localhost:4840/OtOpcUa \
+otopcua-cli alarms -u opc.tcp://localhost:4840/OtOpcUa \
   -n "ns=1;s=TestMachine_001" --refresh
 ```
 
@@ -221,7 +221,7 @@ lmxopcua-cli alarms -u opc.tcp://localhost:4840/OtOpcUa \
 Reads the OPC UA redundancy state from a server: redundancy mode, service level, server URIs, and application URI.
 
 ```bash
-lmxopcua-cli redundancy -u opc.tcp://localhost:4840/OtOpcUa -U admin -P admin123
+otopcua-cli redundancy -u opc.tcp://localhost:4840/OtOpcUa -U admin -P admin123
 ```
 
 Example output:

docs/Client.UI.md

@@ -65,7 +65,7 @@ The top bar provides the endpoint URL, Connect, and Disconnect buttons. The **Co
 
 ### Settings Persistence
 
-Connection settings are saved to `{LocalAppData}/LmxOpcUaClient/settings.json` after each successful connection and on window close. The folder name is a residual from the pre-v2 rename (the `Client.Shared` session factory still calls itself `LmxOpcUaClient` at `OpcUaClientService.cs:428`); renaming to `OtOpcUaClient` is a follow-up that needs a migration shim so existing users don't lose their settings on upgrade. The settings are reloaded on next launch, including:
+Connection settings are saved to `{LocalAppData}/OtOpcUaClient/settings.json` after each successful connection and on window close. Dev boxes upgrading from a pre-task-#208 build still have the legacy `LmxOpcUaClient/` folder on disk; `ClientStoragePaths` in `Client.Shared` moves it to the canonical path on first launch so existing trusted certs + saved settings persist without operator action. The settings are reloaded on next launch, including:
 
 - All connection parameters
 - Active subscription node IDs (restored after reconnection)

src/ZB.MOM.WW.OtOpcUa.Client.CLI/Program.cs

@@ -9,7 +9,7 @@ return await new CliApplicationBuilder()
         if (type.IsSubclassOf(typeof(CommandBase))) return Activator.CreateInstance(type, CommandBase.DefaultFactory)!;
         return Activator.CreateInstance(type)!;
     })
-    .SetExecutableName("lmxopcua-cli")
+    .SetExecutableName("otopcua-cli")
-    .SetDescription("LmxOpcUa CLI - command-line client for the LmxOpcUa OPC UA server")
+    .SetDescription("OtOpcUa CLI - command-line client for the OtOpcUa OPC UA server")
     .Build()
     .RunAsync(args);

src/ZB.MOM.WW.OtOpcUa.Client.Shared/Adapters/DefaultApplicationConfigurationFactory.cs

@@ -18,8 +18,8 @@ internal sealed class DefaultApplicationConfigurationFactory : IApplicationConfi
 
         var config = new ApplicationConfiguration
         {
-            ApplicationName = "LmxOpcUaClient",
+            ApplicationName = "OtOpcUaClient",
-            ApplicationUri = "urn:localhost:LmxOpcUaClient",
+            ApplicationUri = "urn:localhost:OtOpcUaClient",
             ApplicationType = ApplicationType.Client,
             SecurityConfiguration = new SecurityConfiguration
             {
@@ -60,7 +60,7 @@ internal sealed class DefaultApplicationConfigurationFactory : IApplicationConfi
         {
             var app = new ApplicationInstance
             {
-                ApplicationName = "LmxOpcUaClient",
+                ApplicationName = "OtOpcUaClient",
                 ApplicationType = ApplicationType.Client,
                 ApplicationConfiguration = config
             };

src/ZB.MOM.WW.OtOpcUa.Client.Shared/ClientStoragePaths.cs

@@ -0,0 +1,90 @@
+namespace ZB.MOM.WW.OtOpcUa.Client.Shared;
+
+/// <summary>
+///     Resolves the canonical under-LocalAppData folder for the shared OPC UA client's PKI
+///     store + persisted settings. Renamed from <c>LmxOpcUaClient</c> to <c>OtOpcUaClient</c>
+///     in task #208; a one-shot migration shim moves a pre-rename folder in place on first
+///     resolution so existing developer boxes keep their trusted server certs + saved
+///     connection settings on upgrade.
+/// </summary>
+/// <remarks>
+///     Thread-safe: the rename uses <see cref="Directory.Move"/> which is atomic on NTFS
+///     within the same volume. The lock guarantees the migration runs at most once per
+///     process even under concurrent first-touch from CLI + UI.
+/// </remarks>
+public static class ClientStoragePaths
+{
+    /// <summary>Canonical client folder name. Post-#208.</summary>
+    public const string CanonicalFolderName = "OtOpcUaClient";
+
+    /// <summary>Pre-#208 folder name. Used only by the migration shim.</summary>
+    public const string LegacyFolderName = "LmxOpcUaClient";
+
+    private static readonly Lock _migrationLock = new();
+    private static bool _migrationChecked;
+
+    /// <summary>
+    ///     Absolute path to the client's top-level folder under LocalApplicationData. Runs the
+    ///     one-shot legacy-folder migration before returning so callers that depend on this
+    ///     path (PKI store, settings file) find their existing state at the canonical name.
+    /// </summary>
+    public static string GetRoot()
+    {
+        var localAppData = Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData);
+        var canonical = Path.Combine(localAppData, CanonicalFolderName);
+        MigrateLegacyFolderIfNeeded(localAppData, canonical);
+        return canonical;
+    }
+
+    /// <summary>Subfolder for the application's PKI store — used by both CLI + UI.</summary>
+    public static string GetPkiPath() => Path.Combine(GetRoot(), "pki");
+
+    /// <summary>
+    ///     Expose the migration probe for tests + for callers that want to check whether the
+    ///     legacy folder still exists without forcing the rename. Returns true when a legacy
+    ///     folder existed + was moved to canonical, false when no migration was needed or
+    ///     canonical was already present.
+    /// </summary>
+    public static bool TryRunLegacyMigration()
+    {
+        var localAppData = Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData);
+        var canonical = Path.Combine(localAppData, CanonicalFolderName);
+        return MigrateLegacyFolderIfNeeded(localAppData, canonical);
+    }
+
+    private static bool MigrateLegacyFolderIfNeeded(string localAppData, string canonical)
+    {
+        // Fast-path out of the lock when the migration has already been attempted this process
+        // — saves the IO on every subsequent call, + the migration is idempotent within the
+        // same process anyway.
+        if (_migrationChecked) return false;
+
+        lock (_migrationLock)
+        {
+            if (_migrationChecked) return false;
+            _migrationChecked = true;
+
+            var legacy = Path.Combine(localAppData, LegacyFolderName);
+
+            // Only migrate when the legacy folder is present + canonical isn't. Either of the
+            // other three combinations (neither / only-canonical / both) means migration
+            // should NOT run: no-op fresh install, already-migrated, or manual state the
+            // developer has set up — don't clobber.
+            if (!Directory.Exists(legacy)) return false;
+            if (Directory.Exists(canonical)) return false;
+
+            try
+            {
+                Directory.Move(legacy, canonical);
+                return true;
+            }
+            catch (IOException)
+            {
+                // Concurrent another-process-moved-it or volume-boundary or permissions — leave
+                // the legacy folder alone; callers that need it can either re-run migration
+                // manually or point CertificateStorePath explicitly.
+                return false;
+            }
+        }
+    }
+}

src/ZB.MOM.WW.OtOpcUa.Client.Shared/Models/ConnectionSettings.cs

@@ -41,11 +41,11 @@ public sealed class ConnectionSettings
     public bool AutoAcceptCertificates { get; set; } = true;
 
     /// <summary>
-    ///     Path to the certificate store. Defaults to a subdirectory under LocalApplicationData.
+    ///     Path to the certificate store. Defaults to a subdirectory under LocalApplicationData
+    ///     resolved via <see cref="ClientStoragePaths"/> so the one-shot legacy-folder migration
+    ///     runs before the path is returned.
     /// </summary>
-    public string CertificateStorePath { get; set; } = Path.Combine(
+    public string CertificateStorePath { get; set; } = ClientStoragePaths.GetPkiPath();
-        Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
-        "LmxOpcUaClient", "pki");
 
     /// <summary>
     ///     Validates the settings and throws if any required values are missing or invalid.

src/ZB.MOM.WW.OtOpcUa.Client.Shared/OpcUaClientService.cs

@@ -425,7 +425,7 @@ public sealed class OpcUaClientService : IOpcUaClientService
             : new UserIdentity();
 
         var sessionTimeoutMs = (uint)(settings.SessionTimeoutSeconds * 1000);
-        return await _sessionFactory.CreateSessionAsync(config, endpoint, "LmxOpcUaClient", sessionTimeoutMs, identity,
+        return await _sessionFactory.CreateSessionAsync(config, endpoint, "OtOpcUaClient", sessionTimeoutMs, identity,
             ct);
     }
 

src/ZB.MOM.WW.OtOpcUa.Client.UI/Services/JsonSettingsService.cs

@@ -1,4 +1,5 @@
 using System.Text.Json;
+using ZB.MOM.WW.OtOpcUa.Client.Shared;
 
 namespace ZB.MOM.WW.OtOpcUa.Client.UI.Services;
 
@@ -7,9 +8,9 @@ namespace ZB.MOM.WW.OtOpcUa.Client.UI.Services;
 /// </summary>
 public sealed class JsonSettingsService : ISettingsService
 {
-    private static readonly string SettingsDir = Path.Combine(
+    // ClientStoragePaths.GetRoot runs the one-shot legacy-folder migration so pre-#208
-        Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
+    // developer boxes pick up their existing settings.json on first launch post-rename.
-        "LmxOpcUaClient");
+    private static readonly string SettingsDir = ClientStoragePaths.GetRoot();
 
     private static readonly string SettingsPath = Path.Combine(SettingsDir, "settings.json");
 

src/ZB.MOM.WW.OtOpcUa.Client.UI/ViewModels/MainWindowViewModel.cs

@@ -21,9 +21,7 @@ public partial class MainWindowViewModel : ObservableObject
 
     [ObservableProperty] private bool _autoAcceptCertificates = true;
 
-    [ObservableProperty] private string _certificateStorePath = Path.Combine(
+    [ObservableProperty] private string _certificateStorePath = ClientStoragePaths.GetPkiPath();
-        Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
-        "LmxOpcUaClient", "pki");
 
     [ObservableProperty]
     [NotifyCanExecuteChangedFor(nameof(ConnectCommand))]

tests/ZB.MOM.WW.OtOpcUa.Client.CLI.Tests/SubscribeCommandTests.cs

@@ -101,7 +101,8 @@ public class SubscribeCommandTests
         await task;
 
         var output = TestConsoleHelper.GetOutput(console);
-        output.ShouldContain("Subscribed to ns=2;s=TestVar (interval: 2000ms)");
+        // CLI now prints aggregate form "Subscribed to {count}/{total} nodes (interval: ...)" rather than
-        output.ShouldContain("Unsubscribed.");
+        // the single-node form the original test asserted — the command supports multi-node now.
+        output.ShouldContain("Subscribed to 1/1 nodes (interval: 2000ms)");
     }
 }

tests/ZB.MOM.WW.OtOpcUa.Client.Shared.Tests/ClientStoragePathsTests.cs

@@ -0,0 +1,48 @@
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Client.Shared;
+
+namespace ZB.MOM.WW.OtOpcUa.Client.Shared.Tests;
+
+[Trait("Category", "Unit")]
+public sealed class ClientStoragePathsTests
+{
+    [Fact]
+    public void GetRoot_ReturnsCanonicalFolderName_UnderLocalAppData()
+    {
+        var root = ClientStoragePaths.GetRoot();
+        root.ShouldEndWith(ClientStoragePaths.CanonicalFolderName);
+        root.ShouldContain(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData));
+    }
+
+    [Fact]
+    public void GetPkiPath_NestsPkiUnderRoot()
+    {
+        var pki = ClientStoragePaths.GetPkiPath();
+        pki.ShouldEndWith(Path.Combine(ClientStoragePaths.CanonicalFolderName, "pki"));
+    }
+
+    [Fact]
+    public void CanonicalFolderName_IsOtOpcUaClient()
+    {
+        ClientStoragePaths.CanonicalFolderName.ShouldBe("OtOpcUaClient");
+    }
+
+    [Fact]
+    public void LegacyFolderName_IsLmxOpcUaClient()
+    {
+        // The shim depends on this specific spelling — a typo here would leak the legacy
+        // folder past the migration + break every dev-box upgrade.
+        ClientStoragePaths.LegacyFolderName.ShouldBe("LmxOpcUaClient");
+    }
+
+    [Fact]
+    public void TryRunLegacyMigration_Returns_False_On_Repeat_Invocation()
+    {
+        // Once the guard in-process has fired, subsequent calls short-circuit to false
+        // regardless of filesystem state. This is the behaviour that keeps the migration
+        // cheap on hot paths (CertificateStorePath property getter is called frequently).
+        _ = ClientStoragePaths.GetRoot(); // arms the guard
+        ClientStoragePaths.TryRunLegacyMigration().ShouldBeFalse();
+    }
+}

tests/ZB.MOM.WW.OtOpcUa.Client.Shared.Tests/Models/ConnectionSettingsTests.cs

@@ -18,7 +18,7 @@ public class ConnectionSettingsTests
         settings.SecurityMode.ShouldBe(SecurityMode.None);
         settings.SessionTimeoutSeconds.ShouldBe(60);
         settings.AutoAcceptCertificates.ShouldBeTrue();
-        settings.CertificateStorePath.ShouldContain("LmxOpcUaClient");
+        settings.CertificateStorePath.ShouldContain("OtOpcUaClient");
         settings.CertificateStorePath.ShouldContain("pki");
     }
 

tests/ZB.MOM.WW.OtOpcUa.Client.UI.Tests/MainWindowViewModelTests.cs

@@ -252,7 +252,7 @@ public class MainWindowViewModelTests
         _vm.FailoverUrls.ShouldBeNull();
         _vm.SessionTimeoutSeconds.ShouldBe(60);
         _vm.AutoAcceptCertificates.ShouldBeTrue();
-        _vm.CertificateStorePath.ShouldContain("LmxOpcUaClient");
+        _vm.CertificateStorePath.ShouldContain("OtOpcUaClient");
         _vm.CertificateStorePath.ShouldContain("pki");
     }