To dream of a mouse represents a problem or annoyance. A situation that irritates you that it won't go away. Something you don't like having to notice.
To dream of catching a mouse represents a solution to a problem. You don't have to notice something you don't like anymore.
To dream of a white mouse represents problems or annoyances that are being fixed. Alternatively, a white mouse may reflect an annoying person or situation with good intentions that is getting on your nerves.