# Opening Excel Files Locked by Another User/Process with Telerik SpreadProcessing

## Environment

| Version     | Product             | Author                                                                |
| ----------- | ------------------- | --------------------------------------------------------------------- |
| 2025.4.1319 | RadSpreadProcessing | [Yoan Karamanov](https://www.telerik.com/blogs/author/yoan-karamanov) |

## Description

This article shows how to open a file that is already opened by another user or process. Usually, an exception is received because the file is locked for exclusive access. The solution is to open the file in read-only mode without modifying it.

This knowledge base article also answers the following questions:

* How to open locked files in Telerik [SpreadProcessing](https://www.telerik.com/document-processing-libraries/documentation/libraries/radspreadprocessing/overview)?
* How to handle locked file exceptions in [SpreadProcessing](https://www.telerik.com/document-processing-libraries/documentation/libraries/radspreadprocessing/overview)?
* Can [SpreadProcessing](https://www.telerik.com/document-processing-libraries/documentation/libraries/radspreadprocessing/overview) open files in read-only mode?

## Solution

To open a file locked by another user or process, load it into a `MemoryStream` using a read-only `FileStream`. This approach allows concurrent access and bypasses the file lock. Follow these steps:

1. The `FileStream` opens the file with read-only access (`FileAccess.Read`) and allows sharing (`FileShare.ReadWrite`).
2. The `MemoryStream` receives the file contents, enabling the file lock to be released.
3. The [XlsxFormatProvider](https://www.telerik.com/document-processing-libraries/documentation/libraries/radspreadprocessing/formats-and-conversion/import-and-export-to-excel-file-formats/xlsx/xlsxformatprovider) imports the workbook from the `MemoryStream`.

Here is the code example:

```csharp
using Telerik.Windows.Documents.Spreadsheet.Model;
using Telerik.Windows.Documents.Spreadsheet.FormatProviders.OpenXml.Xlsx;

Workbook workbook;
XlsxFormatProvider formatProvider = new XlsxFormatProvider();

// Open file with read-only access and allow sharing for reading and writing
using (FileStream fileStream = new FileStream("file.xlsx", FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
{
    // Copy to memory stream to release file lock immediately
    using (MemoryStream memoryStream = new MemoryStream())
    {
        fileStream.CopyTo(memoryStream);
        memoryStream.Position = 0;

        workbook = formatProvider.Import(memoryStream, null);
    }
}
```

## See Also

* [SpreadProcessing Overview](https://www.telerik.com/document-processing-libraries/documentation/libraries/radspreadprocessing/overview)
* [XlsxFormatProvider](https://www.telerik.com/document-processing-libraries/documentation/libraries/radspreadprocessing/formats-and-conversion/import-and-export-to-excel-file-formats/xlsx/xlsxformatprovider)