When trying to alter a table in MySQL, I get "Error on rename... (Errcode: 13)"

error code 13 can also mean permission denied right? I assume that write permissions have been set? and of course mysql is running.

# is a valid character in windows xp, I assume it would be the same in vista.

Im a little confused though by your comment. You gave sql to add a column but you are talking about the rename of a file

"ALTER TABLE table_name ADD `member_rank` int( 11 ) NULL DEFAULT NULL" Your code is right and error code 13 is regarding permission that means you don't have the right to alter the table.

You can grant user permissiom like this:
USE table_name
GO
GRANT VIEW ANY DEFINITION TO user_name

Yes, my SQL query is correct and yet my MySQL server returned an error message when trying to execute the query.

Eventually it was simply solved by restarting MySQL, but it kept popping up from time to time. Sometimes my tables also locked and newly inserted data disappeared without warning.

In the end I think it had to do with the MySQL service being run with insufficient user permissons in Vista, or the files being protected from modification by the user runnung the MySQL service.

So I changed the security options for the "mysql" folder and subfolders by right clicking on it, choosing "Properties" and going to the "Security" tab. There I made sure that the default user had "Full control" ticked and applied the changes.

Since then I've had none such problems.

PS: It might be interesting for others to know that my invironment (apache, php, mysql) was originally installed via "EasyPHP 2.0b1" so it seems that this application was the one messing things up to start with, perhaps because it wasn't yet fully compatible with Windows Vista.

thanks, this has helped me as well

Thanks, This helped me a lot.