First of all: it's not a software problem or a file problem! It is caused by too large files or too many objects/paths, and the slow running speed and display speed of the software! Sometimes if you use AI for a long time, you will not be able to preview the virtual memory if it is used up or insufficient. In Edit-Preferences-Plugins and Temporary Disks, you can only set other disks. The so-called black outline is the outline preview mode, in order to reduce the burden on CPU and graphics card! To restore, press ctrl+y. Usually do the previous method. Finally, if you still can't preview the colors, you can try to restart your computer. Our school provides free audition activities, and you can audition at any time without making an appointment, so that you can really feel the class level of our school teachers. We are not afraid of comparison, but we are afraid of comparison. We are confident that you can learn the most professional graphic design, and we are confident that you can find a job after you finish it.