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 , at least a first synchronization content message configured to convey progress of a synchronization of a first synchronization content set that includes at least a first electronic content item , where the first synchronization content message 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 ; and transmit, over the communication network 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 , at least a first synchronization content message configured to convey progress of a synchronization of a first synchronization content set that includes at least a first electronic content item , where the first synchronization content message 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 ; and transmit, over the communication network 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 , at least a first synchronization content message configured to convey progress of a synchronization of a first synchronization content set that includes at least a first electronic content item , where the first synchronization content message 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 ; and transmit, over the communication network to the client device , a first message indicating that the synchronization of the first synchronization content set has a likelihood of being prolonged. <EOS>