You might also find your answer in the LastPass Enterprise Manual.
My bookmark set disappearred; how do I restore my bookmarks?
Typically running other bookmark sync extensions in addition to Xmarks is the cause of lost bookmarks. Follow these steps to disable all other sync extensions to prevent future reoccurances.
To restore your bookmarks:
Following the restore, be sure to perform a download in all browsers to update your local sets with your newly restored server set.
If you run into any errors viewing or restoring your bookmark sets, please submit a support ticket including your Xmarks username and the backup number for the bookmark set you're trying to restore.