A multi-threaded processor is configured to detect excepted instructions from a first program, and to stop fetching younger instructions from that same program, to thereby conserve system resources that can be used by other programs. Each fetched program instruction has an associated status bit, which is set if the instruction excepts. Each excepting instruction is logged in an exception logging unit, which causes the associated status bit to be set. Each program has an associated in-flight vector table that tracks the instructions that have been fetched for that program. The status bits are compared with the in-flight vector table to identify the program that is associated with an excepted instruction. That program is then disabled, thereby preventing further fetching of instructions for that program until the excepted instruction clears.