When you reset an experiment, it does not erase the previous data from the experiment. Instead, it puts the experiment into an unstarted state, and every user will receive the default experience. The "salt" used to randomize a user's group will also be changed. This means that when you start the experiment again, your users will be randomly assigned to a group that is not necessarily the same group they were in prior to the experiment being reset. This helps ensure that the new result for the group that was not performing well due to an issue is not negatively affected even after the issue is addressed in the new version.
However, the analysis will restart when you restart the new run, because users’ group assignments will get reshuffled when you restart an experiment. All results, including primary and secondary metrics, will restart fresh when you reset the experiment.
The previous data from the experiment will still be available. You can find the results from the previous run in the experiment’s history. You can refer back to it by clicking on the link provided in the history section.
For more information, you can refer to the Config History Guide.