Hi, I'm trying to upgrade samba 3.6 with openldap backend to samba 4.4.5 through samba classicupgrade process. I'm getting plenty (but not in all entries) of these errors during samba classicupgrade process: "Ignoring group memberships of 'lmecardoso' S-1-5-21-2016195122-1048547273-1752533818-749512: Unable to enumerate group memberships, (-1073741596,This error indicates that the requested operation cannot be completed due to a catastrophic media failure or an on-disk data structure corruption.)" I investigated and some of the users which the error occurred are members of just one posixGroup which have sambaGroupMapping objectClass also while others that performed with no errors are members of a few groups with the same features (posixGroup and sambaGroupMapping). Thus, I can't understand why it's been unable to enumerate group memberships. I tried to read the source code and got nothing interesting to solve this. Any idea on why is this happening and how to avoid that? Thanks in advance Marino