The original manuscripts of The Tale of Genji no longer exist. Royall Tyler writes in the introduction to his translation (Penguin 2003, page xviiii) that by the 13th century, the manuscripts of the work were becoming corrupt, so two scholars independently attempted to restore the text.
Minamoto no Mitsuyuki created a version that is now known as Kawachi-bon (Kawachi text) because he was governor in Kawachi province. Fujiwara no Teika created a version that is now known as Aobyoshi-bon (Aobyoshi text). Royall Tyler makes the following comment about the differences between the two lines of manuscripts:
From the standpoint of the nonspecialist, especially the reader of a translation, there is no striking discrepancy between the Kawachi-bon and Aobyoshi-bon lines, (...)
I assume this means that there are no significant differences at the level of chapter divisions and the plot, but it is not clear at what level of granularity the differences between both lines of manuscripts are to be found. Is this at the level of individual sentences? Individual works? Names of characters? Omission of certain poems?
