diff --git a/apps/desktop/src/main.ts b/apps/desktop/src/main.ts
index 673595830..bb44b93e8 100644
--- a/apps/desktop/src/main.ts
+++ b/apps/desktop/src/main.ts
@@ -25,7 +25,7 @@ async function main() {
     // needed for excalidraw export https://github.com/zadam/trilium/issues/4271
     electron.app.commandLine.appendSwitch("enable-experimental-web-platform-features");
     electron.app.commandLine.appendSwitch("lang", options.getOptionOrNull("formattingLocale") ?? "en");
-    
+
     // Disable smooth scroll if the option is set
     const smoothScrollEnabled = options.getOptionOrNull("smoothScrollEnabled");
     if (smoothScrollEnabled === "false") {
@@ -58,6 +58,27 @@ async function main() {
         electron.globalShortcut.unregisterAll();
     });
 
+    electron.app.on("second-instance", (event, commandLine) => {
+        const lastFocusedWindow = windowService.getLastFocusedWindow();
+        if (commandLine.includes("--new-window")) {
+            windowService.createExtraWindow("");
+        } else if (lastFocusedWindow) {
+            // Someone tried to run a second instance, we should focus our window.
+            // see www.ts "requestSingleInstanceLock" for the rest of this logic with explanation
+            if (lastFocusedWindow.isMinimized()) {
+                lastFocusedWindow.restore();
+            }
+            lastFocusedWindow.show();
+            lastFocusedWindow.focus();
+        }
+    });
+
+    const isPrimaryInstance = (await import("electron")).app.requestSingleInstanceLock();
+    if (!isPrimaryInstance) {
+        console.info("There's already an instance running, focusing that instance instead.");
+        process.exit(0);
+    }
+
     // this is to disable electron warning spam in the dev console (local development only)
     process.env["ELECTRON_DISABLE_SECURITY_WARNINGS"] = "true";
 
diff --git a/apps/server/src/services/window.ts b/apps/server/src/services/window.ts
index 5420a5b43..b26b000af 100644
--- a/apps/server/src/services/window.ts
+++ b/apps/server/src/services/window.ts
@@ -173,22 +173,6 @@ async function createMainWindow(app: App) {
     mainWindow.on("closed", () => (mainWindow = null));
 
     configureWebContents(mainWindow.webContents, spellcheckEnabled);
-
-    app.on("second-instance", (event, commandLine) => {
-        const lastFocusedWindow = getLastFocusedWindow();
-        if (commandLine.includes("--new-window")) {
-            createExtraWindow("");
-        } else if (lastFocusedWindow) {
-            // Someone tried to run a second instance, we should focus our window.
-            // see www.ts "requestSingleInstanceLock" for the rest of this logic with explanation
-            if (lastFocusedWindow.isMinimized()) {
-                lastFocusedWindow.restore();
-            }
-            lastFocusedWindow.show();
-            lastFocusedWindow.focus();
-        }
-    });
-
     trackWindowFocus(mainWindow);
 }
 
@@ -345,6 +329,7 @@ function getAllWindows() {
 
 export default {
     createMainWindow,
+    createExtraWindow,
     createSetupWindow,
     closeSetupWindow,
     registerGlobalShortcuts,
diff --git a/apps/server/src/www.ts b/apps/server/src/www.ts
index 1bef980b2..7f3445312 100644
--- a/apps/server/src/www.ts
+++ b/apps/server/src/www.ts
@@ -55,24 +55,6 @@ export default async function startTriliumServer() {
     tmp.setGracefulCleanup();
 
     const app = await buildApp();
-
-    /**
-     * The intended behavior is to detect when a second instance is running, in that case open the old instance
-     * instead of the new one. This is complicated by the fact that it is possible to run multiple instances of Trilium
-     * if port and data dir are configured separately. This complication is the source of the following weird usage.
-     *
-     * The line below makes sure that the "second-instance" (process in window.ts) is fired. Normally it returns a boolean
-     * indicating whether another instance is running or not, but we ignore that and kill the app only based on the port conflict.
-     *
-     * A bit weird is that "second-instance" is triggered also on the valid usecases (different port/data dir) and
-     * focuses the existing window. But the new process is start as well and will steal the focus too, it will win, because
-     * its startup is slower than focusing the existing process/window. So in the end, it works out without having
-     * to do a complex evaluation.
-     */
-    if (utils.isElectron) {
-        (await import("electron")).app.requestSingleInstanceLock();
-    }
-
     const httpServer = startHttpServer(app);
 
     const sessionParser = (await import("./routes/session_parser.js")).default;