The Bug seems to be kernel related. I restored the last lucid kernel from by backup and using this one the bug is gone.
Latest lucid kernel: Linux 2.6.32-25-generic #44-Ubuntu SMP Fri Sep 17 20:05:27 UTC 2010 x86_64 GNU/Linux -- Maverick corrupts files on samba network shares https://bugs.launchpad.net/bugs/660747 You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to samba in ubuntu. -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
