diff --git a/src/Umbraco.Infrastructure/Sync/SyncBootStateAccessor.cs b/src/Umbraco.Infrastructure/Sync/SyncBootStateAccessor.cs
index e2180cfbcd8a..7daee38b1a23 100644
--- a/src/Umbraco.Infrastructure/Sync/SyncBootStateAccessor.cs
+++ b/src/Umbraco.Infrastructure/Sync/SyncBootStateAccessor.cs
@@ -1,6 +1,8 @@
+using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 using Umbraco.Cms.Core.Configuration.Models;
+using Umbraco.Cms.Core.DependencyInjection;
 using Umbraco.Cms.Core.Services;
 using Umbraco.Cms.Core.Sync;
 
@@ -9,7 +11,7 @@ namespace Umbraco.Cms.Infrastructure.Sync;
 public class SyncBootStateAccessor : ISyncBootStateAccessor
 {
     private readonly ICacheInstructionService _cacheInstructionService;
-    private readonly LastSyncedFileManager _lastSyncedFileManager;
+    private readonly ILastSyncedManager _lastSyncedManager;
     private readonly ILogger<SyncBootStateAccessor> _logger;
     private GlobalSettings _globalSettings;
 
@@ -19,24 +21,53 @@ public class SyncBootStateAccessor : ISyncBootStateAccessor
 
     public SyncBootStateAccessor(
         ILogger<SyncBootStateAccessor> logger,
-        LastSyncedFileManager lastSyncedFileManager,
         IOptionsMonitor<GlobalSettings> globalSettings,
-        ICacheInstructionService cacheInstructionService)
+        ICacheInstructionService cacheInstructionService,
+        ILastSyncedManager lastSyncedManager)
     {
         _logger = logger;
-        _lastSyncedFileManager = lastSyncedFileManager;
+        _lastSyncedManager = lastSyncedManager;
         _globalSettings = globalSettings.CurrentValue;
         _cacheInstructionService = cacheInstructionService;
 
         globalSettings.OnChange(x => _globalSettings = x);
     }
 
+    [Obsolete("Please use the constructor without LastSyncedFileManager. Scheduled for removal in Umbraco 18.")]
+    public SyncBootStateAccessor(
+        ILogger<SyncBootStateAccessor> logger,
+        LastSyncedFileManager lastSyncedFileManager,
+        IOptionsMonitor<GlobalSettings> globalSettings,
+        ICacheInstructionService cacheInstructionService,
+        ILastSyncedManager lastSyncedManager)
+        : this(
+            logger,
+            globalSettings,
+            cacheInstructionService,
+            lastSyncedManager)
+    {
+    }
+
+    [Obsolete("Please use the constructor with ILastSyncedManager. Scheduled for removal in Umbraco 18.")]
+    public SyncBootStateAccessor(
+        ILogger<SyncBootStateAccessor> logger,
+        LastSyncedFileManager lastSyncedFileManager,
+        IOptionsMonitor<GlobalSettings> globalSettings,
+        ICacheInstructionService cacheInstructionService)
+        : this(
+            logger,
+            globalSettings,
+            cacheInstructionService,
+            StaticServiceProvider.Instance.GetRequiredService<ILastSyncedManager>())
+    {
+    }
+
     public SyncBootState GetSyncBootState()
         => LazyInitializer.EnsureInitialized(
             ref _syncBootState,
             ref _syncBootStateReady,
             ref _syncBootStateLock,
-            () => InitializeColdBootState(_lastSyncedFileManager.LastSyncedId));
+            () => InitializeColdBootState(_lastSyncedManager.GetLastSyncedExternalAsync().GetAwaiter().GetResult() ?? -1));
 
     private SyncBootState InitializeColdBootState(int lastId)
     {
diff --git a/tests/Umbraco.Tests.Integration/Umbraco.Infrastructure/Sync/SyncBootStateAccessorTest.cs b/tests/Umbraco.Tests.Integration/Umbraco.Infrastructure/Sync/SyncBootStateAccessorTest.cs
new file mode 100644
index 000000000000..76a0ff0fa4c4
--- /dev/null
+++ b/tests/Umbraco.Tests.Integration/Umbraco.Infrastructure/Sync/SyncBootStateAccessorTest.cs
@@ -0,0 +1,64 @@
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using NUnit.Framework;
+using Umbraco.Cms.Core.Configuration.Models;
+using Umbraco.Cms.Core.Models;
+using Umbraco.Cms.Core.Services;
+using Umbraco.Cms.Core.Sync;
+using Umbraco.Cms.Infrastructure.Persistence.Repositories.Implement;
+using Umbraco.Cms.Infrastructure.Scoping;
+using Umbraco.Cms.Infrastructure.Sync;
+using Umbraco.Cms.Tests.Common.Testing;
+using Umbraco.Cms.Tests.Integration.Testing;
+
+namespace Umbraco.Cms.Tests.Integration.Umbraco.Infrastructure.Sync;
+
+[TestFixture]
+[UmbracoTest(Database = UmbracoTestOptions.Database.NewSchemaPerTest)]
+public class SyncBootStateAccessorTest : UmbracoIntegrationTest
+{
+    private ILastSyncedManager LastSyncedManager => GetRequiredService<ILastSyncedManager>();
+
+    private SyncBootStateAccessor CreateSyncBootStateAccessor() => new(
+        GetRequiredService<ILogger<SyncBootStateAccessor>>(),
+        GetRequiredService<IOptionsMonitor<GlobalSettings>>(),
+        GetRequiredService<ICacheInstructionService>(),
+        LastSyncedManager);
+
+    [Test]
+    public void Returns_ColdBoot_When_No_Last_Synced_Id()
+    {
+        // Arrange - the database is fresh with no last synced id saved
+        var syncBootStateAccessor = CreateSyncBootStateAccessor();
+
+        // Act
+        var result = syncBootStateAccessor.GetSyncBootState();
+
+        // Assert
+        Assert.AreEqual(SyncBootState.ColdBoot, result);
+    }
+
+    [Test]
+    public async Task Returns_WarmBoot_When_Last_Synced_Id_Exists()
+    {
+        // Arrange - create a cache instruction (ID is auto-incremented starting at 1)
+        // and save the last synced external id matching it
+        using (var scope = ScopeProvider.CreateScope())
+        {
+            var repo = new CacheInstructionRepository((IScopeAccessor)ScopeProvider);
+            repo.Add(new CacheInstruction(0, DateTime.Now, "{}", "Test", 1));
+            scope.Complete();
+        }
+
+        // The auto-incremented ID will be 1 in a fresh database
+        await LastSyncedManager.SaveLastSyncedExternalAsync(1);
+
+        var syncBootStateAccessor = CreateSyncBootStateAccessor();
+
+        // Act
+        var result = syncBootStateAccessor.GetSyncBootState();
+
+        // Assert
+        Assert.AreEqual(SyncBootState.WarmBoot, result);
+    }
+}