They were hiding in a Nebula in Year of Hell.
Seven argued that they shouldn't leave until they'd fixed their navigation shields.
Navigation shields are the simple screens powered by a 5 watt battery to stop dust and pebbles perforating Voyager at .25c till it looks like a sieve. It's like trying to fly a plane without a front windshield. This is one of the prime reasons why I'm sure Janeway is a maniac that she believed that her passion would compensate for a lack of navigation shields.
The ship landed for repairs in Nightingale.