Movable partition systems include an elongated, fixed drive member extending along a track, a partition that is automatically and manually movable along the track, and a motor carried by the movable partition configured to drive a rotatable drive member that is engagable with the elongated, fixed drive member. The rotatable drive member may be engaged with, and disengaged from, the fixed drive member. Methods of moving a partition along a track include actuating a motor carried by a movable partition to drive rotation of a drive member while the drive member is engaged with an elongated, fixed drive member, and manually moving the partition along the track while the rotatable drive member is disengaged from the fixed drive member. Methods of installing a movable partition system include configuring a rotatable drive member to be capable of engagement with, and disengagement from, an elongated, fixed drive member.