System.NotSupportedException: No data is available for encoding 1252

.NET Core supports only ASCII, ISO-8859-1 and Unicode encodings, whereas .NET Framework supports much more.

However, .NET Core can be extended to support additional encodings like Windows-1252, Shift-JIS, GB2312 by registering the CodePagesEncodingProvider from the System.Text.Encoding.CodePages NuGet package.

After the NuGet package is installed the following steps as described in the documentation for the CodePagesEncodingProvider class must be done to register the provider:

1. Add a reference to the System.Text.Encoding.CodePages.dll assembly to your project.
2. Retrieve a CodePagesEncodingProvider object from the static Instance property.
3. Pass the CodePagesEncodingProvider object to the Encoding.RegisterProvider method.

What ckuri said. Just to be clear, you need the following line of code before opening the stream (steps 2,3):

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

ExcelDataReader - Important note on .NET Core

By default, ExcelDataReader throws a NotSupportedException "No data is available for encoding 1252." on .NET Core.

To fix, add a dependency to the package System.Text.Encoding.CodePages and then add code to register the code page provider during application initialization (f.ex in Startup.cs):

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

This is required to parse strings in binary BIFF2-5 Excel documents encoded with DOS-era code pages. These encodings are registered by default in the full .NET Framework, but not on .NET Core.

nuget:
Install-Package System.Text.Encoding.CodePages -Version 5.0.0

code:
Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);

I was experiencing similar issue when I was trying to read and convert xlsx file to DataTable. I found out that encoding 1252 are not default in .NET Core therefore I had to separately add NuGet package for the same.

Below is the method where I convert the data from memory stream.

private static DataTableCollection ExcelToDataTable(MemoryStream stream)
{
    System.Text.Encoding.RegisterProvider(System.Text.CodePagesEncodingProvider.Instance);

    using (var reader = ExcelReaderFactory.CreateReader(stream))
    {
        var result = reader.AsDataSet(new ExcelDataSetConfiguration()
        {
            ConfigureDataTable = (data) => new ExcelDataTableConfiguration()
            {
                UseHeaderRow = true
            }
        });
        
        return result.Tables;
    }
}

I referenced the Encoder from nuGet Package at the start of the method and it worked fine for me. This answer is late but might help people who are reading data from streams.

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