When you access a directory in the admin Filelist module, the files in it are automatically indexed, but for a large number of files (about 10.000) this is not a feasible way. Is there a script/command to index an entire directory in FAL?
EDIT: TYPO3 version is 10.4.1 LTS.
There is a scheduled task for that: File abstraction layer: Update storage index. You can set this in the Scheduler. This is only needed if the files are added/removed/changed by something other than the TYPO3 backend (like FTP or a separate import script)