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When you enter TimeMachine you can select the most recent TimeMachine folder that contains all of your missing data folders or files. When you click on {Restore} TimeMachine will attempt to put that folder or file back into its original location. If a folder or file by that name already exists, it will give you the opportunity to "Replace" or "keep Both". If you choose "Keep Both", Time Machine will rename the existing folder or file by appending "(original)" to that folder or file name.
Lightroom will expect to find the files in the location (path) stored in the catalog. If they are exactly where they were before the crash, LR will report no missing files. If not you will need to find the missing folders or files and either put them where LR expects them or point LR to the new location.