A content management system comprising: one or more processors; and one or more computer readable media including instructions which, when executed by the one or more processors, cause the one or more processors to: receive, from a client device over a communication network (102, 406), at least a first synchronization content message (426, 428) configured to convey progress of a synchronization of a first synchronization content set that includes at least a first electronic content item (102, 610), where the first synchronization content message (426, 428) includes information about an amount of data remaining to be synchronized; determine that a synchronization of the first synchronization content set has a likelihood of being prolonged compared to a standard synchronization duration obtained by reference to previous synchronization events for the client device, the determination based at least in part on detection of an atypical synchronization condition being associated with the information of the first synchronization content message (426, 428); and transmit, over the communication network (102, 406) to the client device, a first message indicating that the synchronization of the first synchronization content set has a likelihood of being prolonged. one or more processors; and one or more computer readable media including instructions which, when executed by the one or more processors, cause the one or more processors to: receive, from a client device over a communication network (102, 406), at least a first synchronization content message (426, 428) configured to convey progress of a synchronization of a first synchronization content set that includes at least a first electronic content item (102, 610), where the first synchronization content message (426, 428) includes information about an amount of data remaining to be synchronized; determine that a synchronization of the first synchronization content set has a likelihood of being prolonged compared to a standard synchronization duration obtained by reference to previous synchronization events for the client device, the determination based at least in part on detection of an atypical synchronization condition being associated with the information of the first synchronization content message (426, 428); and transmit, over the communication network (102, 406) to the client device, a first message indicating that the synchronization of the first synchronization content set has a likelihood of being prolonged. receive, from a client device over a communication network (102, 406), at least a first synchronization content message (426, 428) configured to convey progress of a synchronization of a first synchronization content set that includes at least a first electronic content item (102, 610), where the first synchronization content message (426, 428) includes information about an amount of data remaining to be synchronized; determine that a synchronization of the first synchronization content set has a likelihood of being prolonged compared to a standard synchronization duration obtained by reference to previous synchronization events for the client device, the determination based at least in part on detection of an atypical synchronization condition being associated with the information of the first synchronization content message (426, 428); and transmit, over the communication network (102, 406) to the client device, a first message indicating that the synchronization of the first synchronization content set has a likelihood of being prolonged.