Product review (3 stars): When you turn the filter the other way (against the fold) it becomes round and fits easily into the track
For all of you who post the same message: When you turn the filter the other way (against the fold) it becomes round and fits easily into the track. Took me 3 minutes to change it. Don't get discouraged.

But I run mine all day and all night. Needs to be replaced every month minimum. DO NOT LET IT GET DRY IN BETWEEN.