In 'Survey response' area, master users can change votes by others users. What can I do to not allow this?

I don't think there is anything you can do, besides limiting the number of master accesses to a minimum and give it only to trustworthy people.

Limesurvey is made for surveys, not for voting.

In some way, can I get a log of this user?

I wouldn't know how. Maybe the audit-log plugin can help, but I am not sure to what extend things are logged with that plugin.

In the plugins you can activate a audit function, but the log is saved in the database. No viewer is provided.

There isn´t any admin plugin capable of viewing the logs? Any way to export them?

No, not as long as no one writes one. How about you?

Jokes aside: You have the data in the MySQL-Database and you can check it there, export it from there, do what ever you want. But there is no "viewer" that allows you to show the logs.

Hello Holch, I'd really like to write one and will look into this.

While it isn´t ready yet, one more doubt: I´m a professional hosting user, in this case how can I access the database to extract the log info?

OK, prfessional hosting is a whole different thing. Here in the forum we can help with most things LS related, especially for the community version. But when it comes to the professional hosting and the specifics I have no idea, as I am not part of Limesurvey GmbH, but rather do community support in my spare time.

So I don't know if you are even able to access those logs in the professional hosting. You should open a ticket under "contact us" to get support directly from Limesurvey GmbH, which is responsible for the professional hosting.

Thank you for the answer again Holch!
I´ve opened a support ticket and there is one way to have access to the logs: by downloading the database.

Choose 'Configuration/Backup entire database' to download it.

Thank you all for the help.

De nada.