Troubleshooting

macOS Terminal showing zsh: command not found: gti after a typo, beside a table of the five causes and their one-command fixes: typo (command -v), not installed (brew install), not on PATH (add to ~/.zprofile), just installed (rehash), and local script (./script with chmod +x).

“zsh: command not found” on macOS: Causes and Fixes

by Marcus Reeve
August 7, 2026July 19, 2026

When the Terminal prints zsh: command not found: something, it means zsh looked through every directory on your PATH and didn’t find a program by that name. zsh has been the default shell since Catalina…

Three verified macOS Terminal commands in a table: printf '%s' "user:pw" | base64 gives dXNlcjpwdw==; base64 -d

How to Encode and Decode Base64 on macOS

by Marcus Reeve
August 5, 2026July 19, 2026

macOS ships a base64 command at /usr/bin/base64, so there’s nothing to install — it’s the FreeBSD version, which differs from the GNU one on Linux in a couple of ways worth knowing. This covers encoding…

Dark card headed Mac DFU mode: revive or restore, comparing two operations: REVIVE reinstalls firmware and keeps your data (try first), and RESTORE erases the drive and installs a clean macOS (fallback), with a note that it runs from Finder on a second Mac running macOS 14 or later over USB-C

How to Put a Mac in DFU Mode (and Revive or Restore It)

by Marcus Reeve
July 30, 2026July 21, 2026

DFU mode is the deepest recovery state on a Mac. DFU stands for Device Firmware Update, and you reach for it in the rare case where a Mac will not turn on, stops at a…

Dark terminal card headed Two ways to hide a file, showing ls -lO output where flagged.txt carries hidden in the file flags column while visible.txt carries a dash, and ls -ldO on the Library folder showing it also carries the hidden flag despite having no dot in its name, with labels reading a leading dot or the hidden flag and user name redacted

How to Show Hidden Files on a Mac

by Marcus Reeve
July 27, 2026July 20, 2026

There is a keyboard shortcut that shows hidden files in the Finder immediately, and for most people that is the entire answer. What trips people up comes after: some files stay out of sight even…

Two macOS terminal panels: one running tail -f install.log with fresh softwareupdated lines captioned that new lines mean it is still installing, the other running df -h on the data volume showing available space, captioned to keep 50 GB free before upgrading

Mac Update Stuck? How to Tell If It’s Frozen or Just Working

by Marcus Reeve
July 20, 2026July 20, 2026

A macOS update that looks frozen — the bar stuck in one place for an hour, or “less than a minute remaining” that never ends — is usually still working. A big update spends long…

Breakdown of the 37 Mac models Apple lists as compatible with macOS Tahoe 26 across 7 product families, with 4 still Intel-based

macOS Tahoe Compatibility: Every Supported Mac Model

by Marcus Reeve
July 17, 2026July 18, 2026

Whether your Mac can run macOS Tahoe 26 is not a judgment call — Apple publishes a fixed list of model names, and a machine is either on it or it isn’t. The list below reproduces Apple’s compatibility page exactly as Apple words it,… Read More

Side-by-side comparison of startup recovery paths: Apple silicon uses the power button for startup options, while Intel Macs use Option, Command-R and D key combinations

Mac Folder With Question Mark: What It Means and Fixes

by Marcus Reeve
July 17, 2026July 18, 2026

A folder with a flashing question mark is one of the few Mac startup screens that says exactly what it means, once you know how to read it. Apple’s support documentation states that it “means that your computer’s startup… Read More

Two-column fact card explaining why a Mac locks despite display sleep set to Never: on laptops the Screen Saver Start after timer, now under Wallpaper then Screen Saver rather than the Lock Screen pane, triggers it; on desktops with an external display the video signal to the panel is cut about 30 seconds after lock, with no user-facing toggle and not tied to the display-sleep sliders

Mac Screen Keeps Locking or Monitor Keeps Turning Off? The Real Fix

by Marcus Reeve
July 9, 2026July 18, 2026

I ran into the "display set to Never but the Mac locks anyway" problem myself on a MacBook Pro (M3 Max) right after updating to macOS 26.5.2. After testing this across several of my own…

Two schematic panels showing when the macOS Dock moves to an external display: arranged side by side, the Dock moves to the external screen; with the external display arranged above the built-in one, the Dock stays on the built-in screen

Mac Dock Not Moving to External Display on macOS Tahoe [Fix]

by Marcus Reeve
July 1, 2026July 18, 2026

If you’ve spent the last hour dragging your cursor to the bottom of your external monitor hoping the Dock will finally follow — and it hasn’t — you’re not doing anything wrong. This is a…

Fix “packages_dispatcher is not responding” Error in macOS Packages App | 2025 Solution

by Marcus Reeve
December 6, 2025July 17, 2026

If you’re using Packages (the popular macOS installer creation tool by Stéphane Sudre) and suddenly encounter the frustrating “packages_dispatcher is not responding” error during build, you’re not alone.… Read More