320
The file was already open for write operations by another process, but permission to read the file was still obtained.
Initially, the file could not be opened. However, when the ZipOpenedFiles property is set to True, Xceed Zip will attempt to open the file in a shared mode. When this happens, this warning will occur. You might want to make sure that you aren't zipping a file who's contents are being modified by another process at the same time as the zipping operation.