(covers information from several alternate timelines)
On day one of the "Year of Hell", a Krenim patrol ship intercepted and attacked the USS Voyager, claiming it violated a disputed region of Krenim space, which the Voyager crew believed was Zahl territory.
On day 32, Commander Chakotay suggested that the crew break into smaller groups and leave Voyager behind in shuttles and escape pods on separate courses before rendezvousing on the other side of Krenim space. This proposal was rejected by Captain Kathryn Janeway. (VOY: "Year of Hell")
On day 161, Chakotay discovered on Annorax's Krenim weapon ship in 2374 that eight months earlier, component 37329 caused Voyager to set a course so the ship would avoid it completely, which led to them entering Krenim space. Chakotay suggested that Annorax remove the comet from the timeline, so Voyager would not encounter the Krenim Imperium and be severely damaged by their ships. However, upon running a simulation, it was discovered that removing component 37329 from time would result in the removal of eight thousand civilizations, all life in an area of fifty light years.
When the timeline was later negated, Voyager encountered a Krenim ship when they entered Krenim space. The commandant, the same commandant that had attacked the ship in the negated timeline, informed them the region was in dispute and advised they avoid Krenim territory. Captain Janeway thanked him for the warning and Voyager altered course without incident. (VOY: "Year of Hell, Part II")