Information encountering (IE) often occurs during active information-seeking and involves passively finding unsought, unexpected information that is subjectively considered interesting, useful or potentially useful. While the idealized IE process involves engaging with information after noticing it (e.g. by examining it, conducting follow-up seeking to determine usefulness, then using or sharing it), the process can be disrupted -resulting in missed opportunities for knowledge and insight creation. This study provides a detailed understanding of when and why the process can be disrupted. Thinkaloud observations and Critical Incident Interviews were conducted with fifteen Web users, focusing on examining when they encountered information but did not engage with it. Factors that discouraged engagement and simultaneously encouraged participants to return to active, goal-directed informationseeking by disrupting the IE process were identified. These factors individually and collectively demonstrate IE can instigate a highly uncertain cost-benefit trade-off, sometimes resulting in encounterers being cautious by returning to 'less risky' active seeking. Design suggestions are made for reducing the uncertainty of deciding whether to engage with encountered information and making it easier to return to the active seeking task if disruption occurs.