I have the same issue as others and think its energy saver i think the problem is related to cataline which now splits a system to two internal volumes / = the root volume defualts as /volume/Macintosh HD and /System/Volumes/Data which is mounted to various directorys on root /volume/Macintosh HD is mainly system stuff which the user doesnt need to access it also contains the default macOS apps. and /System/Volumes/Data is all the data which the user(s) can change and access thirdpary apps, home directories etc this is how spotlight should be on a defualt catalinea system [sometimes you will have timemachine volumes aswell when its running] > sudo mdutil -sa /: Indexing enabled. /System/Volumes/Data: Indexing enabled. sometimes i find after i plugin in the power cable that System/Volumes/Data isnt re-enabled and sometimes its both volumes that fail to reenable. >mdutil -s -a /: Indexing disabled. /System/Volumes/Data: Indexing disabled. /Volumes/.timemachine/Rendezvous._smb._tcp.local./6A9FBFD7-D3AB-49CC-84A8-2D107EB28BB3/Time Machine Folder: No index. /Volumes/Time Machine Backups: Indexing enabled. /Volumes/Time Machine Backups/Backups.backupdb: Indexing enabled. this means that i can only find defaullt apps through spotlight (and applications which use the service such as Alfred), apps like office and parallels are missing and no documents. As explained i also find that those volumes are removed from search results as opposed to just pausing indexing so the system has to rebuild them once reenabled.