From 28be079779d4508b5ab2a2fd4b482f3fd929ced5 Mon Sep 17 00:00:00 2001
From: orut34iop <orut34iop@users.noreply.github.com>
Date: Tue, 15 Sep 2026 11:16:56 -0400
Subject: Backport pull request #18006 from jellyfin/release-12.z

Preserve active scans when requesting a background library refresh

Original-merge: 949e0585a65a91f90644a2475c1e1009e5d51e90

Merged-by: crobibero <cody@robibe.ro>

Backported-by: Cody Robibero <cody@robibe.ro>
---
 Emby.Server.Implementations/Library/LibraryManager.cs | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

(limited to 'Emby.Server.Implementations')

diff --git a/Emby.Server.Implementations/Library/LibraryManager.cs b/Emby.Server.Implementations/Library/LibraryManager.cs
index f97cc7a0a0..2b3ccd5c99 100644
--- a/Emby.Server.Implementations/Library/LibraryManager.cs
+++ b/Emby.Server.Implementations/Library/LibraryManager.cs
@@ -318,7 +318,7 @@ namespace Emby.Server.Implementations.Library
 
             if (wizardChanged)
             {
-                _taskManager.CancelIfRunningAndQueue<RefreshMediaLibraryTask>();
+                QueueLibraryScan();
             }
         }
 
@@ -3799,7 +3799,7 @@ namespace Emby.Server.Implementations.Library
 
                 if (refreshLibrary)
                 {
-                    StartScanInBackground();
+                    _ = StartScanInBackground();
                 }
                 else
                 {
@@ -3867,13 +3867,16 @@ namespace Emby.Server.Implementations.Library
             }
         }
 
-        private void StartScanInBackground()
+        internal Task StartScanInBackground()
         {
-            Task.Run(() =>
+            // An active scan already handles library structure changes, so this request can be dropped.
+            if (IsScanRunning)
             {
-                // No need to start if scanning the library because it will handle it
-                ValidateMediaLibrary(new Progress<double>(), CancellationToken.None);
-            });
+                return Task.CompletedTask;
+            }
+
+            // Queue instead of restarting so a scan that starts after the check is allowed to finish.
+            return Task.Run(QueueLibraryScan);
         }
 
         public void AddMediaPath(string virtualFolderName, MediaPathInfo mediaPath)
@@ -3984,7 +3987,7 @@ namespace Emby.Server.Implementations.Library
                 {
                     await ValidateTopLibraryFolders(CancellationToken.None, true).ConfigureAwait(false);
 
-                    StartScanInBackground();
+                    _ = StartScanInBackground();
                 }
                 else
                 {
-- 
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