Repository: microsoft/PowerToys
File: src/modules/launcher/Plugins/Microsoft.Plugin.Program/Storage/Win32ProgramRepository.cs (C#)

Code before:
                _fileSystemWatcherHelpers[index].Filters = extensionsToWatch;

                // Registering the event handlers
                _fileSystemWatcherHelpers[index].Created += OnAppCreated;
                _fileSystemWatcherHelpers[index].Deleted += OnAppDeleted;
                _fileSystemWatcherHelpers[index].Renamed += OnAppRenamed;
                _fileSystemWatcherHelpers[index].Changed += OnAppChanged;

                // Enable the file system watcher
                _fileSystemWatcherHelpers[index].EnableRaisingEvents = true;

                // Enable it to search in sub folders as well
                _fileSystemWatcherHelpers[index].IncludeSubdirectories = true;
            }
        }

        private void OnAppRenamed(object sender, RenamedEventArgs e)
        {
            string oldPath = e.OldFullPath;
            string newPath = e.FullPath;

            string extension = Path.GetExtension(newPath);
            Win32Program.ApplicationType oldAppType = Win32Program.GetAppTypeFromPath(oldPath);
            Programs.Win32Program newApp = Win32Program.GetAppFromPath(newPath);
            Programs.Win32Program oldApp = null;

            // Once the shortcut application is renamed, the old app does not exist and therefore when we try to get the FullPath we get the lnk path instead of the exe path
            // This changes the hashCode() of the old application.
            // Therefore, instead of retrieving the old app using the GetAppFromPath(), we construct the application ourself
            // This situation is not encountered for other application types because the fullPath is the path itself, instead of being computed by using the path to the app.
            try
            {
                if (oldAppType == Win32Program.ApplicationType.ShortcutApplication || oldAppType == Win32Program.ApplicationType.InternetShortcutApplication)
                {
                    oldApp = new Win32Program() { Name = Path.GetFileNameWithoutExtension(e.OldName), ExecutableName = Path.GetFileName(e.OldName), FullPath = newApp?.FullPath ?? oldPath };
                }
                else
                {
                    oldApp = Win32Program.GetAppFromPath(oldPath);
                }
            }
            catch (Exception ex)
            {
                Log.Exception($"OnAppRenamed-{extension} Program|{e.OldName}|Unable to create program from {oldPath}", ex, GetType());
            }

            // To remove the old app which has been renamed and to add the new application.
            if (oldApp != null)
            {
                if (string.IsNullOrWhiteSpace(oldApp.Name) || string.IsNullOrWhiteSpace(oldApp.ExecutableName) || string.IsNullOrWhiteSpace(oldApp.FullPath))
                {

Review comment (suggestion):
We cannot do in this way.

I will suggest to move all the created, renamed, etc, with a async wrapper.
We can use the "Task.Run" to call the async wrapper, so that each of them can use await Task.Delay(XXXX).

If not, right now, we are blocking for event handling queue for 1 second, and it can cause other problem.

Code after:
                _fileSystemWatcherHelpers[index].Filters = extensionsToWatch;

                // Registering the event handlers
                _fileSystemWatcherHelpers[index].Created += OnAppCreated;
                _fileSystemWatcherHelpers[index].Deleted += OnAppDeleted;
                _fileSystemWatcherHelpers[index].Renamed += OnAppRenamed;
                _fileSystemWatcherHelpers[index].Changed += OnAppChanged;

                // Enable the file system watcher
                _fileSystemWatcherHelpers[index].EnableRaisingEvents = true;

                // Enable it to search in sub folders as well
                _fileSystemWatcherHelpers[index].IncludeSubdirectories = true;
            }
        }

        private void OnAppRenamed(object sender, RenamedEventArgs e)
        {
            string oldPath = e.OldFullPath;
            string newPath = e.FullPath;

            // fix for https://github.com/microsoft/PowerToys/issues/34391
            // the msi installer creates a shortcut, which is detected by the PT Run and ends up in calling this OnAppRenamed method
            // the thread needs to be halted for a short time to avoid locking the new shortcut file as we read it, otherwise the lock causes
            // in the issue scenario that a warning is popping up during the msi install process.
            System.Threading.Thread.Sleep(1000);

            string extension = Path.GetExtension(newPath);
            Win32Program.ApplicationType oldAppType = Win32Program.GetAppTypeFromPath(oldPath);
            Programs.Win32Program newApp = Win32Program.GetAppFromPath(newPath);
            Programs.Win32Program oldApp = null;

            // Once the shortcut application is renamed, the old app does not exist and therefore when we try to get the FullPath we get the lnk path instead of the exe path
            // This changes the hashCode() of the old application.
            // Therefore, instead of retrieving the old app using the GetAppFromPath(), we construct the application ourself
            // This situation is not encountered for other application types because the fullPath is the path itself, instead of being computed by using the path to the app.
            try
            {
                if (oldAppType == Win32Program.ApplicationType.ShortcutApplication || oldAppType == Win32Program.ApplicationType.InternetShortcutApplication)
                {
                    oldApp = new Win32Program() { Name = Path.GetFileNameWithoutExtension(e.OldName), ExecutableName = Path.GetFileName(e.OldName), FullPath = newApp?.FullPath ?? oldPath };
                }
                else
                {
                    oldApp = Win32Program.GetAppFromPath(oldPath);
                }
            }
            catch (Exception ex)
            {
                Log.Exception($"OnAppRenamed-{extension} Program|{e.OldName}|Unable to create program from {oldPath}", ex, GetType());
            }