cifs.log shows the following messages whenever a user renames a directory from a Windows 7/Mac client (1), or access his home directory from a Mac client (2).
May 20 16:58:15 hec5 CIFS[11203]: EVENT: RPC: Received rename event for volume: SAV, old path: /Test2, new path: /Test3
May 20 16:58:15 hec5 CIFS[11203]: ERROR: RPC: RenameCacheEntries: Failed to get the cache entry of old path: /Test2 (might be already renamed from CIFS), error: 156
May 20 11:02:45 hec1 CIFS[9856]: WARNING: CODIR: User do not have privilege to create file /DATA/Contrats assistants/.DS_Store in this directory.
May 20 11:02:45 hec1 CIFS[9856]: ERROR: CODIR: LockCache failed to open file for User : efournie ,Conn no : 124 ,Err : ERR_NO_CREATE_PRIVILEGE, ErrCode : 132, Path : /DATA/Contrats assistants/.DS_Store

No difference if the volume is in a cluster or not.

The users receive no error messages, only the log grows bigger.

I migrated from OES2SP3 to OES11SP2 : message (2) was already present before the migration, and message (1) is new after migration.

I have reset cifs and NSS settings to standards, but no changes.

Thanks for any idea.