Ошибка system io filenotfoundexception

• The error only happens in production (not in debugging).
• The error only happens on the first application run after Windows login.
• The error occurs when we click BtnUseDesktop and thus fire the BtnUseDesktop_Click event (below).
• The Event Viewer stack starts with the The.Application.Name.Main() method…
• but our code does not have that method (it’s a WPF application).

Event Viewer

 Application: The.Application.Name.exe
 Framework Version: v4.0.30319
 Description: The process was terminated due to an unhandled exception.
 Exception Info: System.IO.FileNotFoundException
 Stack:

   at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(
      System.Object, System.Delegate, System.Object, Int32, System.Delegate)

   at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(
      System.Windows.Threading.DispatcherPriority, System.TimeSpan, 
      System.Delegate, System.Object, Int32)

   at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr, Int32, IntPtr, IntPtr)

   at MS.Win32.UnsafeNativeMethods.DispatchMessage(System.Windows.Interop.MSG ByRef)

   at System.Windows.Threading.Dispatcher.PushFrameImpl(
      System.Windows.Threading.DispatcherFrame)

   at System.Windows.Threading.Dispatcher.PushFrame(
      System.Windows.Threading.DispatcherFrame)

   at System.Windows.Threading.Dispatcher.Run()

   at System.Windows.Application.RunDispatcher(System.Object)

   at System.Windows.Application.RunInternal(System.Windows.Window)

   at System.Windows.Application.Run(System.Windows.Window)

   at The.Application.Name.Main()

BtnUseDesktop_Click

private void BtnUseDesktop_Click(object sender, RoutedEventArgs e)
{
    AvSwitcher switcher = new AvSwitcher();
    this.RunAsyncTask(() => 
        switcher.SwitchToDesktop(this.windowSyncSvc.ActiveLyncWindowHandle));
}

The AvSwitcher that the Click Event Calls Into

public class AvSwitcher
{
    private DeviceLocationSvc deviceLocationSvc;
    private UIAutomationSvc uiAutomationSvc;
    private WindowMovingSvc windowMovingSvc;
    private ManualResetEvent manualResetEvent;
    private Modality audioVideo;
    public static bool IsSwitching { get; set; }

    public AvSwitcher()
    {            
        this.deviceLocationSvc = new DeviceLocationSvc();
        this.uiAutomationSvc = new UIAutomationSvc();
        this.windowMovingSvc = new WindowMovingSvc();
    }

    public void SwitchToDesktop(IntPtr activeLyncConvWindowHandle)
    {
        this.BeginHold(DeviceLocation.Desktop, activeLyncConvWindowHandle);
    }

    public void SwitchToWall(IntPtr activeLyncConvWindowHandle)
    {
        this.BeginHold(DeviceLocation.Wall, activeLyncConvWindowHandle);
    }

    private Conversation GetLyncConversation()
    {
        Conversation conv = null;
        if (LyncClient.GetClient() != null)
        {
            conv = LyncClient.GetClient().ConversationManager.Conversations.FirstOrDefault();
        }

        return conv;
    }

    private void BeginHold(DeviceLocation targetLocation, IntPtr activeLyncConvWindowHandle)
    {
        AvSwitcher.IsSwitching = true;

        // make sure the class doesn't dispose of itself
        this.manualResetEvent = new ManualResetEvent(false);

        Conversation conv = this.GetLyncConversation();
        if (conv != null)
        {
            this.audioVideo = conv.Modalities[ModalityTypes.AudioVideo];
            ModalityState modalityState = this.audioVideo.State;

            if (modalityState == ModalityState.Connected)
            {
                this.HoldCallAndThenDoTheSwitching(targetLocation, activeLyncConvWindowHandle);
            }
            else
            {
                this.DoTheSwitching(targetLocation, activeLyncConvWindowHandle);
            }
        }
    }

    private void HoldCallAndThenDoTheSwitching(
        DeviceLocation targetLocation, 
        IntPtr activeLyncConvWindowHandle)
    {
        try
        {
            this.audioVideo.BeginHold(
                this.BeginHold_callback,
                new AsyncStateValues()
                {
                    TargetLocation = targetLocation,
                    ActiveLyncConvWindowHandle = activeLyncConvWindowHandle
                });
            this.manualResetEvent.WaitOne();
        }
        catch (UnauthorizedAccessException)
        {
            // the call is already on hold
            this.DoTheSwitching(targetLocation, activeLyncConvWindowHandle);
        }
    }

    private void BeginHold_callback(IAsyncResult ar)
    {
        if (ar.IsCompleted)
        {
            DeviceLocation targetLocation = ((AsyncStateValues)ar.AsyncState).TargetLocation;
            IntPtr activeLyncConvWindowHandle = 
                ((AsyncStateValues)ar.AsyncState).ActiveLyncConvWindowHandle;
            this.DoTheSwitching(targetLocation, activeLyncConvWindowHandle);
        }

        Thread.Sleep(2000); // is this necessary
        this.audioVideo.BeginRetrieve(this.BeginRetrieve_callback, null);
    }

    private void DoTheSwitching(DeviceLocation targetLocation, IntPtr activeLyncConvWindowHandle)
    {
        DeviceLocationSvc.TargetDevices targetDevices = 
            this.deviceLocationSvc.GetTargetDevices(targetLocation);

        this.SwitchScreenUsingWinApi(targetDevices.Screen, activeLyncConvWindowHandle);
        this.SwitchVideoUsingLyncApi(targetDevices.VideoDevice);
        this.SwitchAudioUsingUIAutomation(
            targetDevices.MicName, 
            targetDevices.SpeakersName, 
            activeLyncConvWindowHandle);

        AvSwitcher.IsSwitching = false;
    }

    private void SwitchScreenUsingWinApi(Screen targetScreen, IntPtr activeLyncConvWindowHandle)
    {
        if (activeLyncConvWindowHandle != IntPtr.Zero)
        {
            WindowPosition wp = 
                this.windowMovingSvc.GetTargetWindowPositionFromScreen(targetScreen);
            this.windowMovingSvc.MoveTheWindowToTargetPosition(activeLyncConvWindowHandle, wp);
        }
    }

    private void SwitchVideoUsingLyncApi(VideoDevice targetVideoDevice)
    {
        if (targetVideoDevice != null)
        {
            LyncClient.GetClient().DeviceManager.ActiveVideoDevice = targetVideoDevice;
        }
    }

    private void SwitchAudioUsingUIAutomation(
        string targetMicName, 
        string targetSpeakersName, 
        IntPtr activeLyncConvWindowHandle)
    {
        if (targetMicName != null && targetSpeakersName != null)
        {
            AutomationElement lyncConvWindow = 
                AutomationElement.FromHandle(activeLyncConvWindowHandle);

            AutomationElement lyncOptionsWindow =
                this.uiAutomationSvc.OpenTheLyncOptionsWindowFromTheConvWindow(lyncConvWindow);

            this.uiAutomationSvc.SelectTheTargetMic(lyncOptionsWindow, targetMicName);

            this.uiAutomationSvc.SelectTheTargetSpeakers(lyncOptionsWindow, targetSpeakersName);

            this.uiAutomationSvc.InvokeOkayButton(lyncOptionsWindow);
        }
    }

    private void BeginRetrieve_callback(IAsyncResult ar)
    {
        this.audioVideo.EndRetrieve(ar);
        this.manualResetEvent.Set(); // allow the program to exit
    }

    private class AsyncStateValues
    {
        internal DeviceLocation TargetLocation { get; set; }

        internal IntPtr ActiveLyncConvWindowHandle { get; set; }
    }
}

This is the third part in the series named Debugging common .NET exceptions. Today, I want to help you track down and fix a very common and very well-known exception, System.IO.FileNotFoundException. Admitted! In all instances this error is caused by trying to access a file that isn’t there. But, there are actually multiple scenarios that can trigger this exception. You may think you know everything there is to know about this exception, but I bet there is something left for you to learn. At least I did while digging down into the details for this post. Stay tuned to get the full story.

Types of file not found errors

Let’s dig into the different causes of this error. The Message property on FileNotFoundException gives a hint about what is going on.

Could not find file ‘filename’

As the message says, you are trying to load a file that couldn’t be found. This type of error can be re-created using a single line of code:

try
{
    File.ReadAllText("non-existing.file");
}
catch (FileNotFoundException e)
{
    Console.WriteLine(e.ToString());
}

line 3 is the important one here. I’m trying to load a file that doesn’t exist on the file system (non-existing.file). In the example above, the program will print output to the console looking similar to this:

System.IO.FileNotFoundException: Could not find file 'APP_PATHbinDebugnon-existing.file'.
File name: 'APP_PATHbinDebugnon-existing.file'
   at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
   at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)
   at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)
   at System.IO.StreamReader..ctor(String path, Encoding encoding, Boolean detectEncodingFromByteOrderMarks, Int32 bufferSize, Boolean checkHost)
   at System.IO.File.InternalReadAllText(String path, Encoding encoding, Boolean checkHost)
   at System.IO.File.ReadAllText(String path)
   at ConsoleApp.Program.Main(String[] args) in APP_PATHProgram.cs:line 19

APP_PATH will be the absolute path to the file that cannot be found. This type of FileNotFoundException actually contains all the information needed to debug the problem. The exception message contains a nice error description, as well as an absolute path to the missing file. If you want to present the user with the path or maybe create the file when not found, there is a nifty property available on FileNotFoundException:

catch (FileNotFoundException e)
{
    File.Create(e.FileName);
}

In the example I simply create the missing file by using the Filename property. I’ve seen code parsing the exception message to get the name of the missing file, which is kind of a downer when the absolute path is available right there on the exception

The system cannot find the file specified. (Exception from HRESULT: 0x80070002)

This error is typically thrown when trying to load an assembly that doesn’t exist. The error can be re-created like this:

try
{
    Assembly.LoadFile("c:\Nonexisting.dll");
}
catch (FileNotFoundException e)
{
    Console.WriteLine(e.ToString());
}

In this scenario, the program still throws a FileNotFoundException. But the exception message is different:

System.IO.FileNotFoundException: The system cannot find the file specified. (Exception from HRESULT: 0x80070002)
   at System.Reflection.RuntimeAssembly.nLoadFile(String path, Evidence evidence)
   at System.Reflection.Assembly.LoadFile(String path)
   at ConsoleApp.Program.Main(String[] args) in APP_PATHProgram.cs:line 20

Unlike the error thrown on reading the missing file, messages from the System.Reflection namespace are harder to understand. To find the cause of this error you will need to look through the stack trace, which hints that this is during Assembly.LoadFile. Notice that no filename is present in the exception message and in this case, the Filename property on FileNotFoundException is null.

Could not load file or assembly ‘assembly’ or one of its dependencies. The system cannot find the file specified.

An error similar to the one above is the Could not load file or assembly 'assembly' or one of its dependencies. The system cannot find the file specified. error. This also means that the program is trying to load an assembly that could not be found. The error can be re-created by creating a program that uses another assembly. Build the program, remove the references assembly (the .dll file) from the binDebug folder and run the program. In this case, the program fails during startup:

Unhandled Exception: System.IO.FileNotFoundException: Could not load file or assembly 'Lib, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified.
   at ConsoleApp.Program.Main(String[] args)

In this example, I’m referencing an assembly named Lib, which doesn’t exist on the disk or in the Global Assembly Cache (GAC).

The typical cause of this error is that the referenced assembly isn’t on the file system. There can be multiple causes of this. To help you debug this, here are some things to check:

1. If you are deploying using a system like Azure DevOps or Octopus Deploy, make sure all the files from the build output are copied to the destination.
2. Right-click the referenced assembly in Visual Studio, click Properties and make sure that Copy Local is set to true:

Access errors when running on IIS

Until now all instances of this error have been a missing file from the disk. I want to round off this post with a quick comment about security. In some cases, the FileNotFoundException can be caused by the user account trying to access the file, and simply don’t have the necessary access. Under optimal circumstances, the framework should throw a System.UnauthorizedAccessException when this happens. But I have seen the issue in the past when hosting websites on IIS. Make sure that the ASP.NET worker process account (or NETWORK SERVICE depending on which user you are using) has access to all files and folders needed to run the application.

To make sure that the app pool user has access:

1. Right-click the folder containing your web application
2. Click Properties
3. Select the Security tab
4. Click Edit…
5. Click Add…
6. Input IIS AppPoolDefaultAppPool in the text area
7. Click Check Names and verify that the user is resolved
8. Click OK
9. Assign Full control to the new user and save

Also make sure to read the other posts in this series: Debugging common .NET exception.

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We know Microsoft.Office.Interop.Excel does not support .Net Core as of now.

So we need to have an alternative to read/write data from excel till then.

In Such case below error will be shown

 Message: 

System.IO.FileNotFoundException: Could not load file or assembly ‘office, Version=15.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c’. The system cannot find the file specified.

IExcelDataReader data reader is an alternative to read data from an excel sheet to a data table/data table collection.

But it has its own limitations, one of such can be seen while we try to write the modified data table back to the excel sheet.

In this case, also we have an alternative now called XLWorkbook. The working of this extension is similar to Microsoft.Office.Interop.Excel.

Here we can pass the modified data table as an argument and save the data to our required excel sheet in the path that we specify.

One such method is given below. Here we open an excel using IExcelDataReader, modify that and save it using XLWorkbook.

Users can split the code and implement it accordingly.

Some more .Net core-specific code changes can also be seen here.

public void AddExcelData(string FilePath)
{

	System.Text.Encoding.RegisterProvider(System.Text.CodePagesEncodingProvider.Instance);

	try
	{

		FileStream stream = File.Open(FilePath, FileMode.Open, FileAccess.ReadWrite);

		//ExcelDataReader Nuget needed
		IExcelDataReader excelReader = null;
		try
		{
			if (FilePath.EndsWith(".xls"))
			{
				excelReader = ExcelReaderFactory.CreateBinaryReader(stream);
			}
			if (FilePath.EndsWith(".xlsx"))
			{
				excelReader = ExcelReaderFactory.CreateOpenXmlReader(stream);
			}

		}
		catch (Exception)
		{
			throw;
		}

		var result = excelReader.AsDataSet(new ExcelDataSetConfiguration()
		{
			ConfigureDataTable = (data) => new ExcelDataTableConfiguration()
			{
				UseHeaderRow = true
			}

		});
		DataTableCollection table = result.Tables;
		
		//gets first sheet
		DataTable curTable = table[0];
		stream.Close();

		curTable.Columns.Add("NewColumn");

		DataRow rw = null;

		//appends new row to the last used row
		rw = curTable.NewRow();
		rw["NewColumn"] = "Row data";
		curTable.Rows.Add(rw);

		//XLWorkbook Nuget needed
		XLWorkbook wb = new XLWorkbook();
		wb.Worksheets.Add(curTable, "Sheet Name");
		
		//overwrites the file
		wb.SaveAs(FilePath);

	}
	catch (Exception e)
	{
		Console.WriteLine("Unable to generate excel : " + e.Message);
	}

}

Hello @stephentoub ,

private static string Xml_Settings_Path = Directory.GetParent(Directory.GetCurrentDirectory()).FullName + @"/VSMP_Settings_File.xml";`

Still have same problem, i have changed path, i haved used Combine metod but always get error in redhat, System.IO.FileNotFoundException: Could not find file ‘/homeVSMP_Setting.xml’.
File name: ‘/homeVSMP_Setting.xml’
at Interop.ThrowExceptionForIoErrno(ErrorInfo errorInfo, String path, Boolean isDirectory, Func`2 errorRewriter) in //src/System.Private.CoreLib/shared/Interop/Unix/Interop.IOErrors.cs:line 24
at Microsoft.Win32.SafeHandles.SafeFileHandle.Open(String path, OpenFlags flags, Int32 mode) in //src/System.Private.CoreLib/shared/Microsoft/Win32/SafeHandles/SafeFileHandle.Unix.cs:line 39
at System.IO.FileStream.OpenHandle(FileMode mode, FileShare share, FileOptions options) in //src/System.Private.CoreLib/shared/System/IO/FileStream.Unix.cs:line 61
at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options) in //src/System.Private.CoreLib/shared/System/IO/FileStream.cs:line 237
at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize) in //src/System.Private.CoreLib/shared/System/IO/FileStream.cs:line 179
at System.Xml.XmlDownloadManager.GetStream(Uri uri, ICredentials credentials, IWebProxy proxy, RequestCachePolicy cachePolicy) in //src/System.Private.Xml/src/System/Xml/XmlDownloadManager.cs:line 27
at System.Xml.XmlUrlResolver.GetEntity(Uri absoluteUri, String role, Type ofObjectToReturn) in //src/System.Private.Xml/src/System/Xml/XmlUrlResolver.cs:line 66
at System.Xml.XmlTextReaderImpl.OpenUrl() in //src/System.Private.Xml/src/System/Xml/Core/XmlTextReaderImpl.cs:line 3087
at System.Xml.XmlTextReaderImpl.Read() in //src/System.Private.Xml/src/System/Xml/Core/XmlTextReaderImpl.cs:line 1206
at System.Xml.XmlLoader.Load(XmlDocument doc, XmlReader reader, Boolean preserveWhitespace) in //src/System.Private.Xml/src/System/Xml/Dom/XmlLoader.cs:line 50
at System.Xml.XmlDocument.Load(XmlReader reader) in //src/System.Private.Xml/src/System/Xml/Dom/XmlDocument.cs:line 1336
at System.Xml.XmlDocument.Load(String filename) in //src/System.Private.Xml/src/System/Xml/Dom/XmlDocument.cs:line 1288