C# console app copying whole directory and free google translate hangs on first file

Question

C# console app copying whole directory and free google translate hangs on first file

Gennady Gurin 231

Hi, I have in my directory some RTF files which I want to translate to a desired language and later append to the same file and continue to the next. It supposed to detect original language (auto). Each file about a page of RTF text.

Here code:


using GoogleTranslateFreeApi;
using System;
using System.Threading.Tasks;
using System.Windows.Forms;

 static async Task Main(string[] args)
 {
string folderPath = @"C:\MY_ORIGINAL_PATH";
string targetLanguageCode = "es"; // Example: "es" for Spanish, "fr" for French, etc.

if (!Directory.Exists(folderPath))
{
    Console.WriteLine("Target directory does not exist.");
    return;
}

// 2. Initialize the Free Google Translator
var translator = new GoogleTranslator();
Language fromLang = Language.Auto;
Language toLang = GoogleTranslator.GetLanguageByISO(targetLanguageCode);

// 3. Process all RTF files in the folder
string[] rtfFiles = Directory.GetFiles(folderPath, "*.rtf");
Console.WriteLine($"Found {rtfFiles.Length} RTF files. Starting translation...");

foreach (string filePath in rtfFiles)
{    
    try
    {
        Console.WriteLine($"Processing: {Path.GetFileName(filePath)}");

        // Using RichTextBox container to safely parse out the RTF syntax
        using (RichTextBox rtb = new RichTextBox())
        {
            // Load the existing RTF file
            string rawRtf = await File.ReadAllTextAsync(filePath);
            rtb.Rtf = rawRtf;

            // Extract pure text for translation (avoids sending RTF code tags to Google)
            string originalPlainText = rtb.Text;

            if (string.IsNullOrWhiteSpace(originalPlainText))
            {
                Console.WriteLine($"Skipping empty file: {Path.GetFileName(filePath)}");
                continue;
            }
            using var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));

            await Task.Delay(200);
            // Request free translation from Google
            try {
                        
                Task<TranslationResult> translationTask = translator.TranslateLiteAsync(originalPlainText, fromLang, toLang);
                        
                TranslationResult result = await translationTask.WaitAsync(cts.Token);

                string translatedText = result.MergedTranslation;

                Console.WriteLine("Translation completed successfully!");

                // Append translation layout cleanly onto the RichTextBox stream
                rtb.AppendText("\n\nSpanish:\n\n");
                rtb.AppendText(translatedText);
                // Save the updated RTF document back to the original file
                await File.WriteAllTextAsync(filePath, rtb.Rtf);
                Console.WriteLine($"Successfully updated: {Path.GetFileName(filePath)}");
            }
            catch (OperationCanceledException)
            {
                Console.WriteLine("Translation timed out on this file. Skipping or retrying...");
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Error translating: {ex.Message}");
            }

                    
        }
    }
    catch (Exception ex)
    {
        Console.WriteLine($"Error processing file {Path.GetFileName(filePath)}: {ex.Message}");
    }
}

What happens is says:" Processing file1" and it is stuck??

Can anyone tell me what to do next?

Thanks in advance

0 comments

2 answers

Your answer

Answer 1

Harry Nguyen (WICLOUD CORPORATION) 445 Microsoft External Staff Moderator

Hi @Gennady Gurin ,

Thank you for sharing the code.

I performed additional debugging and was able to narrow down where execution stops. The application successfully reaches the translation call:

Task<TranslationResult> translationTask = translator.TranslateLiteAsync( 
originalPlainText, 
fromLang, 
toLang);

When inspecting the returned object in the debugger, the method returns a Task with the following state:

Status = WaitingForActivation 
Method = <TranslateLiteAsync>d__24

This indicates that the call itself is not blocking synchronously and that a translation task has been created successfully.

Execution then waits at:

TranslationResult result = await translationTask.WaitAsync(cts.Token);

and does not reach the subsequent statement:

Console.WriteLine("Translation completed successfully!");

Based on these observations, the file-reading and RTF-processing portions of the application appear to be functioning correctly. The code successfully reaches the translation stage, but the translation operation does not complete during execution.

To further isolate the behavior, I would recommend testing the translator separately using a simple hardcoded string. If the same behavior can be reproduced, it would suggest that the issue is independent of the RTF files and is occurring within the translation layer or its interaction with the translation service.

As GoogleTranslateFreeApi is a third-party package, our investigation is limited to the behavior visible from the application side. While we can confirm that the translation task is created successfully, we are unable to verify the library's internal implementation or diagnose its communication with the underlying translation service.

If the behavior persists in a minimal test, you may want to consider evaluating a more actively maintained translation solution, such as an official translation API or another library that is currently supported and updated. This can help determine whether the behavior is specific to the current package and may also provide improved reliability and compatibility over time.

If the behavior can be reproduced consistently, testing an alternative maintained translation library or service may help determine whether the issue is specific to the current package.

If you found my response helpful or informative, I would greatly appreciate it if you could follow this guide for your confirmation

Thank you.

Gennady Gurin 231 Reputation points

2026-10-29T23:16:46.8333333+00:00

Harry Nguyen said: "I would recommend testing the translator separately using a simple hardcoded string".

What does this mean?

Anyway, Google.Cloud. Translate.V3 is a paid service even though it offers 500,000 characters free.

Is there another FREE library out there besides GoogleTranslateFreeApi ?

Let me know thanks to all.
Harry Nguyen (WICLOUD CORPORATION) 445 Reputation points Microsoft External Staff Moderator

2026-10-30T02:46:35.04+00:00
Hi @Gennady Gurin ,

Sorry if that part was unclear. I understand the translation is still getting stuck, so here is what I meant and a quick way to narrow it down. By testing with a hardcoded string, I meant calling the translator with a short fixed text instead of text from your RTF files. This removes the file reading, the RichTextBox step and the folder loop, so you can see whether the translator works on its own.

For example, in a new console app:

using GoogleTranslateFreeApi; var translator = new GoogleTranslator(); Console.WriteLine("Calling translator..."); var result = await translator .TranslateLiteAsync("Hello world", Language.Auto, GoogleTranslator.GetLanguageByISO("es")) .WaitAsync(TimeSpan.FromSeconds(10)); Console.WriteLine(result.MergedTranslation);

If this also hangs or times out, the problem is in the library or its connection to Google, not in your files or code.

If it prints "Hola mundo", the translator works, and the next step is to check what is different when the RTF text is passed in.

For a free alternative, you may want to look at Azure AI Translator, which has a Free (F0) tier that includes 2 million characters per month. You'll need an Azure account to create a Translator resource. As a rough estimate, one page of text is usually around 2,000–4,000 characters, so this could cover a fair number of single-page files depending on how many you need to process. It's also an official service that is maintained by Microsoft.

Each request can be up to 50,000 characters, so you can send a one-page file in a single call. You can use it from C# with the Azure.AI.Translation.Text NuGet package:

using Azure; using Azure.AI.Translation.Text; var client = new TextTranslationClient( new AzureKeyCredential("<your-key>"), "<your-region>"); var response = await client.TranslateAsync("es", originalPlainText); string translatedText = response.Value[0].Translations[0].Text;

If you leave out the source language, it detects it automatically, as your current code does with Language.Auto.

You can find more details in the official documentation:

Azure AI Translator pricing

Quickstart: Azure Translator client libraries (SDKs). This covers creating the Translator resource, getting the key and region, and setting up a C# console app.

Azure Text Translation client library for .NET

I hope this helps clarify things. If it ends up being useful, I would greatly appreciate it if you could follow this guide for your confirmation.

Thank you.
Gennady Gurin 231 Reputation points

2026-10-30T04:17:31.8866667+00:00

will try, I get back, hope over the weekend, thanks for your time. will write back.
Harry Nguyen (WICLOUD CORPORATION) 445 Reputation points Microsoft External Staff Moderator

2026-10-30T06:24:52.5666667+00:00

Hi @Gennady Gurin ,

Thanks for the update. No rush at all. Please feel free to post the results whenever it's convenient for you, and I'll do my best to help you work through the issue from there.

If the information provided so far has been helpful, you may also take a moment to review the answer and follow the guidance below regarding confirmation. Thank you for your cooperation, and I look forward to your update.

Have a great weekend!

Gennady Gurin 231

I modified the code:

And I got the following error:

Calling translator...

API structure error: The library method may be broken or outdated. Details: The method is no longer valid, or something went wrong.

I registered with Microsoft Azure, I have account id, I could not locate the key, I am on east coast, I used "eastus".

Let me know thanks.

using GoogleTranslateFreeApi;
var translator = new GoogleTranslator();
Console.WriteLine("Calling translator...");

try {
    var result = await translator.TranslateLiteAsync("Hello world", Language.Auto, GoogleTranslator.GetLanguageByISO("es")).WaitAsync(TimeSpan.FromSeconds(10));
    Console.WriteLine(result.MergedTranslation);
}
catch (HttpRequestException ex) when (ex.Message.Contains("429"))
{
    // Thrown when your IP is temporarily rate-limited/banned by Google for too many requests
    Console.WriteLine("Rate limit hit (HTTP 429). Google has temporarily blocked this IP address.");
}
catch (HttpRequestException ex)
{
    // Thrown for general network connectivity or DNS issues
    Console.WriteLine($"Network error occurred: {ex.Message}");
}
catch (NotSupportedException ex)
{
    // Thrown when Google updates its API token generation algorithms, breaking the library's internals
    Console.WriteLine($"API structure error: The library method may be broken or outdated. Details: {ex.Message}");
}
catch (Exception ex)
{
    // Fallback block to prevent the application from crashing unexpectedly
    Console.WriteLine($"An unexpected error occurred: {ex.Message}");
}


Console.ReadKey();

Gennady Gurin 231 Reputation points

2026-11-02T06:06:09.18+00:00

I found 2 keys; I got error though.

Let me know, thanks.
Harry Nguyen (WICLOUD CORPORATION) 445 Reputation points Microsoft External Staff Moderator

2026-11-02T06:12:45.17+00:00
Hi @Gennady Gurin ,

Thank you for the update. This is actually progress. The previous test helped confirm that the issue was not related to the RTF files or directory-processing logic. The new error:

Status: 401 (Unauthorized)

indicates that the request is reaching Azure AI Translator, but the service is not accepting the authentication information being supplied.

To help verify the configuration, could you compare your code with the following minimal sample from the Azure AI Translator SDK?

using Azure; using Azure.AI.Translation.Text; string key = "<translator-key>"; string region = "<translator-region>"; var client = new TextTranslationClient( new AzureKeyCredential(key), region); var response = await client.TranslateAsync("es","Hello world"); Console.WriteLine(response.Value[0].Translations[0].Text);

Please ensure that:

The key is KEY 1 or KEY 2 from the Translator resource's Keys and Endpoint page.

The region matches the region shown on that same page.

Both the key and region belong to the same Translator resource.

For security reasons, please do not post the actual key value. However, if the 401 error persists, please share the code used to create the TextTranslationClient (with the key removed), and I'll be happy to take another look. You can also refer to the official Microsoft documentation for setup and configuration:

Quickstart: Azure Translator client libraries (SDKs)

Quickstart: Azure AI Translator REST APIs

I look forward to your update.

If you found my response helpful or informative, I would greatly appreciate it if you could follow this guide for your confirmation

Thank you.
Gennady Gurin 231 Reputation points

2026-11-03T04:49:18.8966667+00:00

The same error 401.

code:

using Azure;

using Azure.AI.Translation.Text;

string key = "<lettersAndnumbershere>";

string region = "<eastus>";

var client = new TextTranslationClient(

new AzureKeyCredential(key),region);

var response = await client.TranslateAsync("es", "Hello world");

Console.WriteLine(response.Value[0].Translations[0].Text);

Console.ReadKey();

I put correct key; I chose a free tier 2million characters per month.
Harry Nguyen (WICLOUD CORPORATION) 445 Reputation points Microsoft External Staff Moderator

2026-11-03T08:15:43.7333333+00:00
Hi @Gennady Gurin ,

Thank you for your patience. I tested the same sample using my own Translator resource and the translation completed successfully. I was also able to reproduce the same 401 Unauthorized response when I intentionally used an invalid key or a region that did not match the resource.

Since your screenshot confirms that the resource region is eastus and the client initialization looks correct, could you please confirm whether you have already tried both KEY 1 and KEY 2 from the Keys and Endpoint page?

If you have only tried one, please test the other key as well. I would also recommend copying the key directly using the Copy button in the Azure portal and running the minimal "Hello world" sample again, keeping the configuration exactly as:

string key = "YOUR_ACTUAL_KEY"; string region = "eastus";

Please make sure there are no < > characters, leading/trailing spaces, or line breaks in the actual values.

If you have already tested both keys and both return the same 401 response, please let me know. In that case, we can rule out an issue specific to one key and focus next on the Translator resource/authentication configuration rather than making unnecessary changes to your application code.

Please continue to keep both key values private when sharing the results.

If you found my response helpful or informative, I would greatly appreciate it if you could follow this guide for your confirmation

Thank you.

Answer 2

Replace GoogleTranslateFreeApi with a maintained translation API; its TranslateLiteAsync implementation has known upstream breakage and may block before returning a Task, so your current WaitAsync is not guaranteed to be reached.^1^^2^

The supported replacement is an official client such as Google.Cloud.Translate.V3; it requires configuring the Google Cloud Translation service, credentials, and billing.^3^

Confirm where execution stops

Your only message is printed before file loading, RTF parsing, and translation. Add checkpoints first:

Console.WriteLine("1: Reading file");
string rawRtf = await File.ReadAllTextAsync(filePath);

Console.WriteLine("2: Parsing RTF");
rtb.Rtf = rawRtf;
string originalPlainText = rtb.Text;

Console.WriteLine($"3: Calling translator ({originalPlainText.Length} chars)");
Task<TranslationResult> task =
    translator.TranslateLiteAsync(originalPlainText, fromLang, toLang);

Console.WriteLine("4: Translator returned a Task");
TranslationResult result =
    await task.WaitAsync(TimeSpan.FromSeconds(10));

Console.WriteLine("5: Translation completed");

Interpret the last message:

Stops after 1: file reading is blocked, possibly by file access or storage.
Stops after 2: the RTF control is the boundary to investigate.
Stops after 3 but never prints 4: TranslateLiteAsync is blocking synchronously before returning its task. No timeout applied afterward can interrupt that call.
Prints 4 and then times out: the asynchronous translation request is not completing.

WaitAsync(TimeSpan) faults with TimeoutException when its timeout expires.^4^ Therefore catch the matching exception:

try
{
    TranslationResult result = await translator
        .TranslateLiteAsync(originalPlainText, fromLang, toLang)
        .WaitAsync(TimeSpan.FromSeconds(10));
}
catch (TimeoutException)
{
    Console.WriteLine("Translation exceeded 10 seconds.");
}

Your existing cancellation-token overload produces OperationCanceledException, but only after execution has reached WaitAsync. It cannot protect against a synchronous stall while TranslateLiteAsync(...) is being invoked.

Temporary containment for the obsolete library

If replacement cannot happen immediately, move the entire invocation onto a worker thread so a synchronous stall does not stop the directory loop:

try
{
    TranslationResult result = await Task.Run(() =>
        translator.TranslateLiteAsync(originalPlainText, fromLang, toLang))
        .Unwrap()
        .WaitAsync(TimeSpan.FromSeconds(15));

    string translatedText = result.MergedTranslation;
}
catch (TimeoutException)
{
    Console.WriteLine("Translator stalled; skipping this file.");
}

This only abandons waiting. It does not cancel the underlying request or terminate a blocked worker thread, so repeated failures could consume thread-pool threads. Treat it as diagnostic or short-term containment, not a production fix.

Keep `RichTextBox` work on an STA thread

A console application does not install a UI SynchronizationContext; after an await, continuation code normally runs on a thread-pool thread.^5^ RichTextBox is a Windows Forms control, and Windows Forms uses the single-threaded apartment model.^6^

Adding [STAThread] to an async Main does not ensure that code after each await returns to the original thread. Either:

move RTF load/extract/append/save operations to a dedicated STA thread, or
remove RichTextBox from the console processing path and use an RTF parser designed for non-UI/background use.

For synchronous STA processing, RichTextBox.LoadFile and SaveFile are preferable to manually reading and writing its Rtf property. LoadFile replaces the control contents and supports RTF directly.^7^

Also write to a temporary output file and replace the original only after translation and RTF serialization succeed. That prevents a failed translation or process termination from corrupting the source document.

References

C# console app copying whole directory and free google translate hangs on first file

2 answers

Confirm where execution stops

Temporary containment for the obsolete library

Keep RichTextBox work on an STA thread

Your answer

Keep `RichTextBox` work on an STA thread