In some sites, locking problems surface as soon as a server is installed; in other sites locking problems may not surface for a long time. Almost without exception, when a locking problem does surface it will cause embarrassment and potential data corruption.
Over the past few years there have been a number of complaints on the Samba mailing lists that have claimed that Samba caused data corruption. Three causes have been identified so far:
Incorrect configuration of opportunistic locking (incompatible with the application being used. This is a common problem even where MS Windows NT4 or MS Windows 200x-based servers were in use. It is imperative that the software application vendors ' instructions for configuration of file locking should be followed. If in doubt, disable oplocks on both the server and the client. Disabling of all forms of file caching on the MS Windows client may be necessary also.
Defective network cards, cables, or HUBs/Switched. This is generally a more prevalent factor with low cost networking hardware, although occasionally there have also been problems with incompatibilities in more up-market hardware.
There have been some random reports of Samba log files being written over data files. This has been reported by very few sites (about five in the past three years) and all attempts to reproduce the problem have failed. The Samba Team has been unable to catch this happening and thus has not been able to isolate any particular cause. Considering the millions of systems that use Samba, for the sites that have been affected by this as well as for the Samba Team this is a frustrating and a vexing challenge. If you see this type of thing happening, please create a bug report on Samba Bugzilla  without delay. Make sure that you give as much information as you possibly can help isolate the cause and to allow replication of the problem (an essential step in problem isolation and correction).
 https ://bugzilla.samba.org
13.6.1 locking.tdb Error Messages
" We are seeing lots of errors in the Samba logs, like :
tdb(/usr/local/samba_2.2.7/var/locks/locking.tdb): rec_read bad magic 0x4d6f4b61 at offset=36116
What do these mean ?"
This error indicated a corrupted tdb. Stop all instances of smbd, delete locking.tdb, and restart smbd.
13.6.2 Problems Saving Files in MS Office on Windows XP
This is a bug in Windows XP. More information can be found in Microsoft Knowledge Base article 812937. 
13.6.3 Long Delays Deleting Files Over Network with XP SP1
" It sometimes takes approximately 35 seconds to delete files over the network after XP SP1 has been applied ."
This is a bug in Windows XP. More information can be found in Microsoft Knowledge Base article 811492.