ElectronNET/Electron.NET · error · Error

BrowserWindow with id

Error message

BrowserWindow with id '${id}' was not found.

What it means

getWindowById in the Electron host's browserWindows.js looks up a BrowserWindow by numeric id among tracked windows and throws a JS Error when no window matches. Every browserWindow API call (focus, destroy check, visibility, modal, maximized state, etc.) resolves its target through this function, so a stale id fails all of them.

Solutions

1. Check the window exists (Electron.WindowManager.BrowserWindow.GetAll()) before operating on it
2. Listen for the window 'closed' event and remove the id from your cache
3. Confirm you are using the BrowserWindow id (element.id), not a webContents or process id
4. Wrap the call so a failed lookup is handled gracefully (e.g. recreate the window)

Example fix

// before
var win = Electron.WindowManager.BrowserWindow.Get(cachedId);
await win.CloseAsync(); // throws if closed
// after
var win = Electron.WindowManager.BrowserWindow.GetAll()
    .FirstOrDefault(w => w.Id == cachedId);
if (win != null) await win.CloseAsync();

const win = electron.BrowserWindow.getAllWindows().find(w => w.id === id);
if (!win) {
    console.warn(`Window ${id} not found; skipping call`);
    return;
}

function windowExists(id) {
    return electron.BrowserWindow.getAllWindows().some(w => w.id === id);
}

try
{
    var win = Electron.WindowManager.BrowserWindow.Get(id);
    await win.CloseAsync();
}
catch
{
    // window already closed — recreate or ignore
    logger.LogInformation("Window {Id} not found; it may already be closed", id);
}

When it happens

Trigger: Calling an Electron.NET BrowserWindow API (e.g. Electron.WindowManager.BrowserWindow.Get(id).Close()) with an id that was never created, or whose window has since been closed/destroyed; using an id from a previous app run.

Common situations: Caching window IDs across app restarts; calling APIs on a window after the user closed it; passing a webContents id or other numeric id instead of a window id; race conditions where the window closed before the IPC call arrived.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

• Unexpected token when reading releaseNotes.
• Invalid value for TitleBarOverlay. Expected boolean or an…
• BrowserWindow with id

AI-assisted analysis of ElectronNET/Electron.NET@87cc6f98b6 (2026-09-14). Data as JSON: /api/errors/871950ef714fa5ae. Report an issue: GitHub.

Appendix: source

Thrown at src/ElectronNET.Host/api/browserWindows.js:713

    socket.on("browserWindowSetVibrancy", (id, type) => {
        getWindowById(id).setVibrancy(type);
    });
    socket.on("browserWindow-setBrowserView", (id, browserViewId) => {
        getWindowById(id).setBrowserView((0, browserView_1.browserViewMediateService)(browserViewId));
    });
    function getWindowById(id) {
        const runtimeWindow = electron_1.BrowserWindow.fromId(id);
        if (runtimeWindow) {
            return runtimeWindow;
        }
        synchronizeWindowRegistry();
        for (let index = 0; index < windows.length; index++) {
            const element = windows[index];
            if (tryGetWindowId(element) === id) {
                return element;
            }
        }
        throw new Error(`BrowserWindow with id '${id}' was not found.`);
    }
    function tryGetWindowId(element) {
        try {
            return element.id;
        }
        catch {
            return null;
        }
    }
    function synchronizeWindowRegistry() {
        const runtimeWindows = electron_1.BrowserWindow.getAllWindows();
        const runtimeWindowIds = new Set(runtimeWindows.map((entry) => entry.id));
        for (let index = windows.length - 1; index >= 0; index--) {
            const windowId = tryGetWindowId(windows[index]);
            if (windowId === null || !runtimeWindowIds.has(windowId)) {
                windows.splice(index, 1);
            }
        }

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