# What to do if you find a bug in a problem

Sometimes a problem in one of the WeBWorK libraries has a mistake — a typo, perhaps it checks answer correctly for some students but not for others, or perhaps there is division by zero for some students but not others.

The reason errors might occur for some students but not all is because the numerical coefficients are different for each student. In some cases these coefficients might pose an ill-determined problem. The coefficients are generated by a pseudo-random number generator from the problem seed. Changing the seed changes the problem.

For a fast solution for a given problem change the seed for that problem for that student. *See How to change a student's problem seed.*

### Instructors and Authors: Reporting the bug

In order to submit the version of the question that is causing the bug, first "Act As" the student whose question is not working. (This could be your own version of the question if all versions have the bug.) Then, while viewing the troublesome question, click "Edit this problem". Above the problem text and to the right you will see the link \"report problem bugs". Clicking the link will take you to Bugzilla, which collects information on all the problem bugs.

The *first* time you report a bug you will be asked to enter your email. Bugzilla will mail you a password which you enter to log into with Bugzilla. You can then change your password to something that is easy to remember. Bugzilla needs your email so that it can tell you when the bug has been fixed.

Once you enter Bugzilla you'll find that the path to the library problem and the problem seed have already been entered in the title. You need only enter a verbal description of what is going wrong. The bug will be filed and reported to those responsible for maintaining the problem library. You will be notified when the problem has been fixed.

To acquire the fixed problem you will have to "update the problem library" from the SVN. *See Subversion.*