Before a paused study can restart, all participants currently active must be given a chance to complete the study. Once all active participants complete the study or abandon the HIT, the study will restart.
When you pause a study to change a setting or temporarily halt data collection, restarting requires waiting until all active participants have either completed the HIT or abandoned it. This means, theoretically, that restarting a HIT may require waiting as long as the maximum time you have given participants to complete your study. The possibility for a long restart time is why we recommend against very long max completion times like 24 hours.
If you paused and restarted your study, you may see a spinning wheel as the system waits for people to complete your HIT before it can be restarted. Once all participants are no longer active within your study, the wheel will go away and your study will be live.