Finder sidebar not showing: find the cause first

The left column of a Finder window disappears, and every search result offers the same answer: choose View, then Show Sidebar. That works about half the time. The rest of the time the menu item is dimmed, or it is already ticked, or it turns the strip back on and the one row that mattered is still absent. Those are three separate faults wearing the same description. Sorting out which one is happening takes about ten seconds and removes most of the guesswork that follows.

Three faults, one description

Look at the window and answer one question: how much is missing.

What is visible	What is actually wrong	Where the fix is
No left column at all	the sidebar is hidden, or the toolbar is	the View menu
A thin edge, no content	the divider was dragged to the far left	the divider itself
Some headings, others gone	a section is collapsed or switched off	the heading, or Finder settings
Everything except one drive	that item is not connected or not selected	Finder settings, or the disk

Each row leads somewhere different, and the fix for one does nothing for the others. Turning the sidebar off and on again is the standard first move, and it only helps the first row of that table.

The whole strip is gone

The menu item is the right place to start. Apple documents both the item and the case where it does not work.

Hide or show the sidebar: In the menu bar, choose View > Hide Sidebar, or View > Show Sidebar. (If Show Sidebar is dimmed, choose View > Show Toolbar.) Source: support.apple.com

The dimmed case catches a lot of people, because nothing on screen explains the dependency. Hiding the toolbar hides the sidebar with it, and the status bar moves from the bottom of the window to the top. A window in that state looks stripped down rather than broken, which is why it often survives for weeks before anyone tries to fix it. The keyboard route is Option-Command-S for the sidebar and Option-Command-T for the toolbar, both listed on Apple's shortcut reference.

One thing to note before hunting for a per window setting: there is not one. Showing the sidebar in a single window shows it in every Finder window on the machine, and the state persists across a restart. If it comes back hidden after every login, something is resetting the Finder preference file rather than the window doing it.

The strip is there, at zero width

The divider between the sidebar and the file list can be dragged all the way to the left edge of the window. Nothing prevents it. The result is a window with the sidebar still switched on and no visible column, and the View menu correctly reports Hide Sidebar because the sidebar is, technically, showing.

The fix is to put the pointer exactly on the left edge of the file list, where it changes to a horizontal resize cursor, and drag right. The width is stored per machine, and it can be read back from the terminal with defaults read com.apple.finder SidebarWidth, which returns a number in points. A value near zero confirms the diagnosis without any dragging at all.

This one is worth checking before anything else when the sidebar vanished immediately after resizing a window. A narrow window and a mistimed drag produce it easily, and no menu item will bring the column back.

There is a related case that looks identical and is not. Dragging the divider far to the right leaves the sidebar filling most of the window and the file list squeezed into a strip, which reads as a broken window rather than a resized one. Both are the same control, and both are corrected the same way, by finding the divider and putting it somewhere sensible. Anything between roughly 150 and 300 points is comfortable, and the default sits near the middle of that range.

A section is collapsed rather than missing

Favorites, iCloud, Locations, and Tags each have a heading, and each heading has a hide control that appears when the pointer moves over it. Collapsing a section leaves the heading in place but removes every row underneath, which reads as a section that has disappeared.

Position the pointer over the heading and the control reappears, in the opposite state. macOS stores each section separately, under preference keys such as SidebarPlacesSectionDisclosedState and SidebarDevicesSectionDisclosedState, so one section can be collapsed for months while the others behave normally.

A heading that is gone entirely is a different matter. Sections disappear when they contain nothing at all. An empty Favorites list means no Favorites heading, and Apple's instructions for adding an item there include selecting at least one entry in Finder settings first, precisely because there is otherwise nothing to drag onto.

A single row that will not appear

This is the most common version of the complaint and the least served by the standard advice. The sidebar is present, the sections are open, and one specific item is missing.

Choose Finder, then Settings, then the Sidebar tab. Every row the sidebar can show is a checkbox there, grouped into the same sections that appear in the window. Hard disks, external disks, CDs and DVDs, connected servers, the home folder, and each iCloud item are all individual switches. Unticking any of them removes the row without any other visible sign.

Two traps live in that panel. The first is that the Sidebar tab and the General tab control different things. General decides what appears on the desktop, Sidebar decides what appears in the left column, and turning off desktop icons for external disks is a common way to end up believing the sidebar setting was changed. The second is that a checkbox only permits a row; it does not create one. An external disk that is unplugged, asleep, or failing to mount produces no row no matter how the box is set, and the place to confirm that is Disk Utility rather than Finder.

Folders added by hand are different again. Those live in the Favorites section as aliases, and they are managed by a background process called sharedfilelistd rather than by the Finder preference file. That is why removing a folder from the sidebar never deletes it, and why a favorite occasionally survives changes that reset everything else in the window.

Tags and iCloud have a second switch

Two sections do not take their rows from the Sidebar tab alone, which is why they resist the usual fix.

Tags have their own tab in Finder settings. The Sidebar tab decides whether the Tags section exists at all, and the Tags tab decides which individual tags are allowed into it. A tag can be in daily use, applied to hundreds of files, and still be absent from the sidebar because it was never marked as a favorite in that second panel. Nothing about the file list gives any hint of the second switch.

The iCloud section has a dependency outside Finder entirely. If iCloud Drive is switched off in System Settings, the rows for iCloud Drive, Desktop, and Documents do not appear regardless of the Sidebar tab, because there is nothing for them to point at. The same applies while a Mac is signed out of its Apple Account. The order to check is System Settings first, Finder settings second, since the Finder checkbox has no effect until the service above it is on.

After a major update, the list is rewritten

macOS runs a migration step on the sidebar during large upgrades, and it leaves a marker behind in the Finder preferences. Reading defaults read com.apple.finder on a machine that has been through several releases shows a stack of keys named in the pattern FXSidebarUpgradedToTenTen, FXSidebarUpgradedToTenFourteen, FXSidebarUpgradedToSixteen, one per version that reorganised the list.

That migration is why a sidebar sometimes comes back after an update with items nobody added, or with a folder from years ago restored to Favorites. It is also why a folder that was removed deliberately can reappear once. Removing it again is enough, because the marker records that the migration already ran and it will not repeat for that version.

The distinction worth holding on to is between a list that changed once, at update time, and a list that keeps reverting at every login. The first is normal. The second points at a Finder preference file that cannot be written, usually because permissions on the home folder were altered, and that is a different repair.

Dialogs keep their own copy

An Open or Save panel shows a sidebar too, and it reads the same favorites list, which is why adding a project folder in Finder makes it available inside every save dialog on the Mac. What it does not share is the layout. The panels store their own width under separate keys, FK_SidebarWidth and FK_SidebarWidth2, and their own show or hide state.

The practical effect is that a sidebar can be perfectly healthy in Finder and collapsed in every save dialog, or the reverse. Fixing one does not fix the other. Each has to be widened where it appears, by dragging the divider inside the dialog itself.

Some applications also draw a file browser that looks like Finder but is not, with a sidebar that only reflects that application's own bookmarks. Those ignore Finder settings completely, and a row missing there is a setting inside that application.

When the list itself is broken

If the sidebar shows the right sections but the rows behave strangely, dimmed entries, duplicates, folders that no longer respond to a click, the list has become stale rather than misconfigured. Relaunching Finder is the low risk step: hold Option and Control while clicking the Finder icon in the Dock, then choose Relaunch. Nothing is lost, and the sidebar is rebuilt from the stored list.

Dimmed rows that stay dimmed usually point at something that is genuinely unavailable. A network share that is no longer reachable, an external drive that has been ejected, or a folder that was deleted after it was added all leave a row behind that cannot be opened. Removing it and adding the folder again is faster than repairing it.

There is a limit worth knowing before spending more time on this. The sidebar is a fixed list of shortcuts, not a view of the file system, and it cannot show two folders side by side or open a shell in the folder that is selected. When the missing row turns out to be a workaround for that limit, the fix is a different window arrangement rather than a different checkbox; the feature list for a file manager with a built-in terminal sets out what changes, and the comparison of the alternatives covers how they differ.

What to change first

Open Finder settings and look at the Sidebar tab before touching anything else, because it explains most single missing rows in one screen. If the whole column keeps vanishing instead, check whether the toolbar is hidden, since that takes the sidebar with it. If neither applies, Atriens collects the sidebar questions that come up most often.