Working model. Recycling of replisome components back into the soluble pool after replication termination is blocked when CMG unloading and replisome disassembly are defective. This leads to lower rates of origin firing at yet-to-fire origins and reduced rate of DNA replication globally. Persistent binding of post-termination replisomes to chromatin during G2 results in accumulation of single-stranded DNA and activation of the ATR–Chk1–Wee1 pathway, which triggers the G2/M checkpoint and blocks entry into mitosis. The mechanism and exact DNA structures that generate single-stranded DNA and RPA binding require further study. KO, knockout; Pol, polymerase.