On a samba 4.2 DC(tested 4.2rc2/rc3/rc4), which has worked well for about a month now. It still works for all users except "Administrator". The problem happen after some time like 15-30 days If I login to a Windows box with the Administrator account, I can't connect to any shares and clicking on a mapped drive returns the error "The security ID structure is invalid". Opening "Active Directory Users and Computers" on the Windows box returns "The RPC server is unavailable". Using "smbclient -L localhost -UAdministrator" on the GNU/Linux server running samba I receife this error: "session setup failed: NT_STATUS_INVALID_SID". tests with heavy support of the samba list (samba@lists.samba.org) has put in evidence two way to resolve the problem. first by Roland Penny https://lists.samba.org/archive/samba/2015-January/188455.html second by Andrew Bartlett https://lists.samba.org/archive/samba/2015-January/188462.html Charles
If you installed Samba 4.2 before rc4, ensure you have run 'net cache flush' to clear the bad cache entry. This issue is fixed in 4.2rc4. Please do not re-open or re-file unless you can reproduce on a domain that was either NOT running a prior version of Samba 4.2, or has already had 'net cache flush' run since the upgrade. *** This bug has been marked as a duplicate of bug 10720 ***