I seem to have found in problem with Ntfs.File.Delete.
Sometimes it throws the exception: Collection was modified; enumeration operation may not execute
I don't know why it happens on some windows servers and not others.
I have traced it down to this:
foreach (var attr in _attributes)
I have replaced with:
for (int i = _attributes.Count - 1; i >= 0; i--)
NtfsAttribute attr = (NtfsAttribute)_attributes[i];
is this ok?