A TWO-STAGE HYDROCRACKING PROCESS EMPLOYING RECYCLE OF HIGH BOILING, SECOND STAGE PRODUCT TO SECOND STAGE FEED AND A SECOND STAGE CATALYST CONTAINING AN IRON GROUP HYDROGENATIVE METAL SUPPORTED ON AN AMORPHOUS SILICAALUMINA-FLUORINE ACID-ACTING BASE ISIMPROVED TO AVOID FORMATION OF POLYAROMATIC COMPOUNDS IN THE HIGH BOILING PRODUCT BY (A) FIRST DISCONTINUING THE FLOW OF HYDROCARBON FEED TO THE SECOND-STAGE, (B) THEN CONTACTING THE SECOND STAGE CATALYST WITH OXYGEN, (C) CONTACTING THE OXIDIZED SECOND STAGE CATALYST WITH A SULFIDING COMPOUND AT CONDITIONS TO CONVERT THE IRON GROUP METAL COMPONENT TO A SULFIDE FORM, (D) CONTACTING THE SECOND STAGE CATALYST WITH FROM ABOUT 0.001% TO ABOUT 0.2 WT. OF CATALYST OF FLUORINE IN THE FORM OF A VAPOR PHASE FLUORIDING COMPOUND AT A TEMPERATURE OF FROM 350* TO 1100*F., AND (E) RE-ESTABLISHING THE FLOW OF HYDROCARBON FEED TO THE SECOND-STAGE.