程序已经在运行了，不能运行两次。\n如果右下角软件已经退出，请在任务管理器中结束ToastFish任务。

Error message

程序已经在运行了，不能运行两次。\n如果右下角软件已经退出，请在任务管理器中结束ToastFish任务。

What it means

In Form_Load (View/ToastFish.xaml.cs:105), called from the MainWindow constructor, the app derives its own executable name and calls Process.GetProcessesByName; if more than one process with that name exists, it concludes a second instance was started and shows this MessageBox before closing the current window. This is a single-instance guard meant to prevent duplicate tray icons and conflicting SQLite access — the second launch is intentionally terminated.

Solutions

Do nothing extra: the current (duplicate) instance closes itself. Use the already-running instance's tray icon.
If no live instance is visible, open Task Manager, end the ToastFish task as the dialog instructs, then relaunch.
Run "taskkill /IM ToastFish.exe /F" (adjust to the exe name) to clear stale/hung instances, then start the app once.
Check Startup entries (Task Manager > Startup, shell:startup) and remove duplicates so only one auto-start exists.
Prefer a named Mutex single-instance check over process-name counting in code, since name-based detection misfires with renamed copies.

Example fix

// before
if (processes.Length > 1) { MessageBox.Show("程序已经在运行了..."); this.Close(); }
// after
private static Mutex _mutex;
_mutex = new Mutex(true, "ToastFish.SingleInstance", out bool createdNew);
if (!createdNew) { MessageBox.Show("程序已经在运行了，不能运行两次。"); this.Close(); return; }

Defensive patterns

Strategy: validation

Validate before calling

// check for an existing instance before initializing UI
using var mutex = new Mutex(true, "ToastFish.SingleInstance", out bool createdNew);
if (!createdNew)
{
    System.Windows.Forms.MessageBox.Show("程序已经在运行了，不能运行两次。\n如果右下角软件已经退出，请在任务管理器中结束ToastFish任务。", "提示");
    return; // abort startup
}

Try / catch

try
{
    // single-instance check in Program.Main / Form_Load
}
catch (Exception ex)
{
    // process enumeration can fail under restricted environments
    System.Diagnostics.Debug.WriteLine($"single-instance check failed: {ex.Message}");
}

Prevention

Remember that closing the window does not exit the app — check the system tray first.
Avoid double-adding the exe to Startup entries.
Use a named Mutex instead of Process.GetProcessesByName for reliable single-instance enforcement.
If a previous instance hangs, kill it via Task Manager or taskkill before relaunching.

When it happens

Trigger: Launching ToastFish.exe while another instance is already running (tray icon still alive after window was 'closed'), or when a stale process with the same executable name is running (e.g. a hung instance, a renamed copy, or the app started twice at login).

Common situations: User clicks the exe again thinking the app exited because the window closed while the tray process persists; two shortcuts in the Startup folder; app pinned and also auto-started; a frozen previous instance that must be killed via Task Manager as the message itself instructs; running a copied/renamed exe that collides with the original name.

Related errors

AI-assisted analysis of Uahh/ToastFish@2508784a66 (2026-09-15). Data as JSON: /api/errors/8c828bf0a244308d. Report an issue: GitHub.

Appendix: source

Thrown at View/ToastFish.xaml.cs:105

                    break;
                default:
                    break;
            }           
        }

        private void Form_Load()

        {
            //获取当前活动进程的模块名称
            string moduleName = Process.GetCurrentProcess().MainModule.ModuleName;
            //返回指定路径字符串的文件名
            string processName = System.IO.Path.GetFileNameWithoutExtension(moduleName);
            //根据文件名创建进程资源数组
            Process[] processes = Process.GetProcessesByName(processName);
            //如果该数组长度大于1，说明多次运行
            if (processes.Length > 1)
            {
                System.Windows.Forms.MessageBox.Show("程序已经在运行了，不能运行两次。\n如果右下角软件已经退出，请在任务管理器中结束ToastFish任务。", "提示", MessageBoxButtons.OK, MessageBoxIcon.Information);//弹出提示信息
                this.Close();//关闭当前窗体
            }
        }

        private void SetNotifyIcon()
        {
            Vm.notifyIcon = new NotifyIcon();
            Vm.notifyIcon.Text = "ToastFish";
            System.Drawing.Icon icon = IconChika.chika16;

            Vm.notifyIcon.Icon = icon;
            Vm.notifyIcon.Visible = true;
            Vm.notifyIcon.DoubleClick += Begin_Click;
            //Vm.notifyIcon.DoubleClick += NotifyIconDoubleClick;
        }

        public void PlayMute()
        {

View on GitHub (pinned to 2508784a66)