From what you have described so far I would hazard that someone is "experimenting" with the data in question, probably using some other tool.

You might ask the network people if there is some way they can trace who has accessed and REVISED the tables in the directories in question. Better yet, they may be able to restrict access to only the application(s) in question.

good luck


>After this happened, this part of the program that made use of the extracted data was not usable.
>The extracts were done again yesterday night and the users are using the application without any problems.
>
>The tables are part of a database and on Monday the .dbc file was the one that was modified.