If a problem has been found in an active index, or you want to diagnose issues using a staging environment, you can use the History tab to redeploy an old index.
To deploy an old index:
In the Administration Options menu, go to Projects > Your Project > Indexing > History tab.
Click the Deploy icon () for the index.
Select the environment to which to deploy the index.
Click OK to confirm.
Note: The next index you perform must be complete. You cannot index incrementally from a restored old index.