C # creates ZipArchive with many files

My method takes a list and creates a zip file and a log file. It works with fewer files. But when I go after a lot of files (checked with 11,000) it throws a SystemOutOfMemory exception.

From my research, I found out that my method is probably using most of the memory. So I included this part to clear the streamblock and zip archive. I probably should do something for the file stream.

What is an effective approach to solving this problem?

Here is the code:

        public static void BackupFilesToZip(string directory, string fileFilter, string zipFilePath, bool backupInSubDir, string logFilePath, List<FileInfo> filesToBackup)
    {
        FileInfo logFile = new FileInfo(logFilePath);
        FileInfo zipFile = new FileInfo(zipFilePath);
        int numberOfFiles = filesToBackup.Count;

        if (!Directory.Exists(zipFile.DirectoryName)) Directory.CreateDirectory(zipFile.DirectoryName);

        using (FileStream zipToOpen = new FileStream(zipFile.FullName, FileMode.OpenOrCreate))
        {
            using (ZipArchive archive = new ZipArchive(zipToOpen, ZipArchiveMode.Update))
            {
                ZipArchiveEntry readmeEntry = archive.CreateEntry(logFile.Name);
                using (StreamWriter writer = new StreamWriter(readmeEntry.Open()))
                {
                    writer.WriteLine("This ZIP archive was created: " + DateTime.Now.ToString("MM/dd/yy HH:mm:ss"));
                    writer.WriteLine("ZIP File: " + zipFilePath);
                    writer.WriteLine("Source Directory: " + directory);
                    string backupInSubText = "yes";
                    if (!backupInSubDir) backupInSubText = "no";
                    writer.WriteLine("Subdirectories included: " + backupInSubText);
                    writer.WriteLine("Filter Critera: " + fileFilter);
                    writer.WriteLine("Number of Files selected: " + numberOfFiles + " (for # of files archived/skipped scroll down)");
                    writer.WriteLine("");
                    writer.WriteLine("File Log:");

                    int filesArchivedCounter = 0;
                    int filesSkippedCounter = 0;
                    int filesSum = 0;

                    TaskbarManager.Instance.SetProgressState(TaskbarProgressBarState.Normal);

                    foreach (FileInfo file in filesToBackup)
                    {
                        //ZipArchiveEntry readmeEntry = archive.CreateEntry(logFile.Name);
                        string DateTimeStampBegin = DateTime.Now.ToString("MM/dd/yy HH:mm:ss");

                        try
                        {
                            string relativePath = MakeRelativePath(directory, file.FullName);
                            archive.CreateEntryFromFile(file.FullName, relativePath);
                            writer.WriteLine(DateTimeStampBegin + " - " + DateTime.Now.ToString("HH:mm:ss") + " archived: " + file.FullName);
                            filesArchivedCounter++;
                        }
                        catch
                        {
                            writer.WriteLine(DateTimeStampBegin + " - " + " SKIPPED: " + file.FullName);
                            filesSkippedCounter++;
                        }

                        filesSum = filesSkippedCounter + filesArchivedCounter;
                        TaskbarManager.Instance.SetProgressValue(filesSum, numberOfFiles);

                        //write from memory to files every 75 items (to avoid out of memory exception)
                        if (filesSum % 75 == 0)
                        {
                            writer.Flush();
                            zipToOpen.Flush();
                        }
                    }

                    writer.WriteLine("");
                    writer.WriteLine("# of Files archived: " + filesArchivedCounter);
                    writer.WriteLine("# of Files skipped: " + filesSkippedCounter);
                }

                if (!String.IsNullOrEmpty(logFile.Name))
                {
                    if (!Directory.Exists(logFile.DirectoryName)) Directory.CreateDirectory(logFile.DirectoryName);
                    readmeEntry.ExtractToFile(logFile.FullName, true);
                }

                TaskbarManager.Instance.SetProgressState(TaskbarProgressBarState.NoProgress); 
            }
        }
    }

      

        
        
        
      

    

All string parameters to this method are for the log file only.