A grade of "Incomplete" is given when a student who has been doing passing work in a course is unable to complete the course work, due to serious circumstances which arose during the Semester. In general, before giving such a grade, an instructor will require some documentation of the circumstances (e.g., a doctor's note if the problem was medical).
An undergraduate student receiving an Incomplete is expected to make up the remaining work in the course by the first day of classes of the second Semester after the grade was received. (So if you get an "I" at the end of Spring Semester or Summer Session of one year, you have till the first day of classes of the next Spring Semester to make it up, while if you get it at the end of a Fall Semester, you have till the first day of classes of the next Fall Semester. These deadlines may be extended with the approval of a Dean.) When this has been done, the student should obtain a "Removal of Incomplete" form from Sproul Hall, pay a fee (currently $5) and have it endorsed there, and bring it to the instructor, who will fill in the grade the student should be assigned and file the form. The student's records will then be adjusted to show that the Incomplete has been made up, and the new grade will be counted in the student's GPA. (The above deadlines and procedures do not apply to graduate students; they should look in the General Catalog for rules applying to them. However, the the remaining paragraphs apply to both undergraduates and graduates.)
How is the work to be made up? If only a small piece of material has to be completed, the instructor may accept the work from the student and grade it. If the work to be completed is more extensive, the commonest procedure is to arrange with an instructor teaching the course the next Semester to allow the student to participate and do all the work for the course, and have that instructor assign the student a grade, and communicate it to the original instructor. The original instructor will then use this grade on the "Removal of Incomplete" form. In any case, the student should arrange ahead of time with the instructor who gave the Incomplete how the grade is to be made up. If that instructor is no longer in Berkeley, the student should instead contact the Department in which the course is taught.
Note that if a student makes up an Incomplete by participating in the class the following Semester, he or she must do this without officially re-enrolling in the course. If the student re-enrolls in the course while the "I" still stands (without obtaining special permission from a Dean), the "I" will automatically be changed into an "F". This will also happen if the time limit for making up the "I" passes without the grade being removed. This "F" may then be superseded in the student's GPA by a grade obtained by re-enrolling in the course and passing it, but it will remain visible as an F on the student's transcript.
Students wishing to make up Incompletes by participating in the course during a Summer Session should be aware that (1) the Summer Session will require such students to pay an auditor's fee, equal to the fee paid by students regularly enrolled in the Summer Session course, and (2) not all courses given during the year are given in Summer Session.
There are some less commonly used options, such as "freezing" an Incomplete, or graduating before the Incomplete has changed to an F, which you can read about in the General Catalog. The Catalog also contains rules about maximum numbers of Incomplete grades a student may hold, obtaining extensions of the deadline for making up an Incomplete, etc..
Note for students seeking an I grade. If your need for an "I" results from circumstances that have affected most of the courses you are taking, and you get a large number of "I"'s, you may put yourself in the difficult position of trying to make them up at the same time that you will be carrying regular loads of other classes. In such a case, it might be best to instead go to the Dean's Office of your College to discuss alternative possibilities, such as a late withdrawal from school for this Semester. Likewise, if you were unable to complete the course due to serious problems, but the circumstances do not fit the criteria for an Incomplete, it might instead be possible to get a retroactive withdrawal from the course with the approval of a Dean.