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

Sometimes a problem in one of the WeBWorK libraries has a mistake, maybe a typo, or perhaps it checks answer correctly for some students but not for others, or there might be 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, so 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 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 address so the system can mail you a temporary password (and later notify you when the problem has been remedied). Log into Bugzilla with your temporary password and then change it to something easy to remember.

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.

The fixed problem will be saved in the WeBWorK Open Problem Library on github. To install the fixed problem on your webwork server so you can use it, the person in charge of your webwork server must update update the problem library on your server. For instructions, see *Open_Problem_Library* and scroll down to "Updating the OPL".