How macOS actually works

The hidden folders a Mac leaves on drives

Updated 2026-10-30 · 4 min read

These folders are macOS bookkeeping for the drive, not your files. All but .Trashes can go once the drive is away from the Mac, and only some of them can be kept from coming back.

What each folder is

A Mac adds a few hidden folders to the top of drives it mounts. Windows and other devices that show hidden items will list them. To see them in Terminal, use the drive's name as it appears in ls /Volumes:

ls -la "/Volumes/<DriveName>"

Folder	What it is	Safe to delete?
.Spotlight-V100	Spotlight's search index for that drive	Yes, from another computer. It returns when a Mac indexes the drive again
.fseventsd	The log macOS keeps of changes made on that drive	Yes, from another computer. A Mac recreates it
.Trashes	The drive's own Trash: files you deleted from the drive in Finder	Look first. They are your deleted files
.TemporaryItems	Working files apps can leave while saving to that drive	Normally harmless; no Apple page describes it, so this is from how it behaves

Files named ._something and .DS_Store come from the same Mac but are a separate subject with their own fixes.

Apart from .Trashes, none of these hold your documents, so deleting them elsewhere leaves your files alone.

Why .Trashes matters more than the others

.Trashes is the one that can hold data you care about. When you delete a file from an external drive in Finder, it goes into that drive's .Trashes, not onto the Mac's internal disk, and the drive's space only comes back when the Trash is emptied while the drive is still connected. That's why a drive can look just as full after you've deleted things.

So before you unplug a drive for use elsewhere, empty the Trash with the drive attached: choose Finder > Empty Trash… or press ⇧⌘⌫. Deleting .Trashes by hand on another computer deletes the files in it too, so check you don't want any back first; files in the Trash shows how.

Why they appear, and how far you can stop them

.Spotlight-V100

Spotlight indexes the drive so it can be searched. Two ways to keep the drive out of Spotlight:

• System Settings > Spotlight, click Search Privacy, then add the drive (the label on macOS 15.6 and in Apple's current guide). Older macOS versions had a Privacy tab in Spotlight preferences instead.
• In Terminal: sudo mdutil -i off "/Volumes/<DriveName>". The mdutil manual describes -i off as setting indexing off for that volume; changing indexing needs administrator rights, hence sudo, which asks for your password.

Neither guarantees the folder disappears. Howard Oakley's Eclectic Light Company notes that volumes keep their hidden .Spotlight-V100 folder even with Spotlight's indexing switched off, just with an empty index inside. To check what you did took effect, run mdutil -s "/Volumes/<DriveName>" (no sudo needed).

There's also a marker file. mdutil on macOS 15.6 still carries the status message "Indexing and searching disabled because of ".metadata_never_index" file at root of volume", which suggests Spotlight still honours that file at the top of a drive:

touch "/Volumes/<DriveName>/.metadata_never_index"

It travels with the drive, which suits drives other people plug into their Macs. Eclectic Light reports the same file no longer works inside an ordinary folder on recent macOS, so use it only at the top of the drive and confirm with mdutil -s. For the Mac side, see Spotlight and external drives.

.fseventsd

This is the file system events log, explained in what fsevents is. Apple's FSEvents programming guide, last updated in 2012, says you can stop the logging on one volume with an empty file named no_log inside a .fseventsd folder at the top of it. The folder belongs to the system on a Mac, so the commands need sudo:

sudo mkdir -p "/Volumes/<DriveName>/.fseventsd"
sudo touch "/Volumes/<DriveName>/.fseventsd/no_log"

Two caveats. The folder stays, holding that one empty file, so it won't make the drive look tidier. And Apple's documentation is old: in a 2025 thread on Apple's developer forums, a developer reported no_log seemed not to work on macOS 15.5, and Apple's engineer replied that he'd still expect it to work in theory, but not on the startup volume. For a stick that just needs to look clean on a TV or a PC, deleting .fseventsd there is simpler.

.Trashes and .TemporaryItems

Empty the Trash with the drive connected, then eject it. They come back the next time you delete something on that drive from a Mac.

What Everywhere shows of them

Everywhere skips anything named .Spotlight-V100, .fseventsd, .Trashes, .TemporaryItems or .DocumentRevisions-V100, so a search of a USB stick lists your files, not Spotlight's index pages or event logs. The flip side: a file waiting in a drive's .Trashes won't show up there, so open the Trash itself to look for it. External drives are indexed once Everywhere has Full Disk Access, and each one can be switched off in its External Drives menu.

Common questions

What is the .fseventsd folder on a USB drive?

It's the log macOS keeps of changes made on that drive, and it holds no documents. Another computer can delete it safely, and a Mac recreates it the next time it mounts the drive.

Can I delete .Spotlight-V100 from a USB drive?

Yes, on another computer. It's only Spotlight's index for that drive and returns when a Mac indexes it again. To keep the index from being built, add the drive to Spotlight's Search Privacy list or run sudo mdutil -i off on it.

What is the .Trashes folder on a USB drive?

The drive's own Trash. Files you delete from it in Finder wait there and keep using space until you empty the Trash with the drive connected.

How do I stop my Mac creating hidden files on USB drives?

You can't stop all of them. Turn off Spotlight indexing for the drive and empty the Trash before ejecting, which keeps .Spotlight-V100 small and .Trashes empty, then delete what's left on the other computer. .DS_Store and ._ files have their own fixes.