Link-state routing protocols (e.g. OSPF or IS-IS) are known to converge to a loop-free state within a finite period of time after a change in the topology. It is normal, however, to observe short-term loops during the period of topology update propagation, route recalculation, and forwarding table update, due to the asynchronous nature of link-state protocol operation. This document provides an analysis of formation of such microloops and suggests simple mechanisms to minimize them.