When deleting files from the file system, the stream was interrupted

I am getting the "Thread was aborted" error when I try to delete some temporary files from a specific directory. I think this problem is specific to the code below, because the application pool is not being recycled while the code is running (as far as I noticed). The part of the code below works successfully if it takes 3-5 seconds. But when there are more files, I get an error after 12 or 15 seconds. I am assuming it is not a global timeout etc., because there are other threads taking much longer than this and still not interrupted. Could this be related to I / O operations? This is a piece of code:

DateTime now = DateTime.Now;
IEnumerable<string> directories = Directory.EnumerateDirectories(_pathOfTempFiles);
directories= directories.Concat(new[] { _pathOfTempFiles }); 
foreach (string dirPath in directories)
{

    DirectoryInfo di = new DirectoryInfo(dirPath);
    foreach (FileInfo fi in di.EnumerateFiles())
    {
        if (now.Subtract(fi.CreationTime).TotalHours >= 2 && !fi.Name.ToLower().Contains("web.config") && !fi.Name.ToLower().Contains("web.confıg"))
        {                        
            try
            {
                fi.Delete();                            
            }
            catch (Exception ex)
            {                                                        
                _messages.Add("Exception : " + ex.Message + " ~ " + fi.Name);

            }
        }
    }
}