Here's a quick reference guide to common Mac issues, organized by symptom. Each section links to a detailed guide with step-by-step solutions.
Table of Contents
Performance Issues
If your Mac feels slow, unresponsive, or laggy, the cause could range from low storage to outdated software or too many login items. A restart is the quickest fix, but there are several other steps worth trying.
How to Fix a Slow Mac | Troubleshooting by Cause
Storage Issues
Running out of storage prevents you from saving files, installing updates, and can even slow down your Mac. Cleaning up files, leveraging iCloud, and using macOS's built-in tools can reclaim plenty of space.
How to Free Up Mac Storage | Tips for Recovering Disk Space
Battery Issues (MacBook)
If your MacBook's battery drains faster than expected, it may be caused by power-hungry apps, display settings, or battery degradation. Start by checking which apps are using the most energy.
How to Fix MacBook Battery Draining Fast | Troubleshooting by Cause
Black Screen
If your Mac's screen goes black — power is on but the Apple logo never appears, the display fails to wake from sleep, or an external monitor takes over and the built-in screen disappears — the fix depends on which stage fails. The linked guide walks through power and cable basics, force restart, SMC and NVRAM resets (Intel Mac only), Safe Mode boot, login items and system extensions, macOS Recovery, and DFU mode in order. Both Apple Silicon (M1/M2/M3/M4) and Intel Macs are covered.
How to Fix a Black Screen on Mac | Sleep Wake-Up, Boot Failure, and Post-Login Cases
Mac Won't Start
If pressing the power button does nothing, the Mac freezes at the Apple logo or a progress bar, restarts repeatedly after login (login loop), shows a flashing folder with a "?" mark, or displays a kernel panic screen — the diagnosis depends on which stage of startup is failing. The linked guide walks through power and peripheral checks, force shutdown, Safe Mode, SMC and NVRAM resets (Intel Mac only), Disk Utility First Aid in macOS Recovery, macOS reinstall, and DFU restore via Apple Configurator 2 (Apple Silicon) in priority order. Both Apple Silicon (M1/M2/M3/M4) and Intel Macs are covered.
How to Fix a Mac That Won't Start | Power Failure, Apple Logo Stuck, and Login Loop Diagnosis
Frozen / Unresponsive Mac
If only one app stops responding (the spinning rainbow cursor), the entire system feels sluggish including Finder, or the mouse and keyboard are completely unresponsive — the right fix depends on which symptom you're seeing. The linked guide covers force quitting individual apps with Cmd+Option+Esc, identifying CPU- and memory-hungry processes in Activity Monitor, restarting Finder, force shutdown via the power button, killing processes from Terminal, handling memory pressure, SMC and NVRAM resets (Intel Mac only), Safe Mode diagnosis, and prevention. Both Apple Silicon (M1/M2/M3/M4) and Intel Macs are covered.
What to Do When Your Mac Freezes | Force Quit Apps vs Activity Monitor vs SMC Reset by Symptom
Keyboard Not Working
If your Mac's built-in keyboard, Magic Keyboard, or Bluetooth keyboard suddenly stops responding — entire keyboard dead, only specific keys not registering, input cutting out mid-typing, or working at the login screen but not after sign-in — the cause depends on which case you're in. The linked guide covers the Accessibility Keyboard fallback, Bluetooth re-pairing, SMC and NVRAM resets (Intel Mac only), IME-specific diagnosis, Safe Mode, login items and Karabiner-Elements, and final repair decisions in priority order. Both Apple Silicon (M1/M2/M3/M4) and Intel Macs are covered.
How to Fix a Keyboard Not Working on Mac | Built-in, Magic Keyboard, and Bluetooth Diagnosis
Wi-Fi Not Connecting
If your Mac sees the SSID but won't join, the password keeps getting rejected, the connection is fine but speeds are sluggish, Wi-Fi drops after sleep, or only specific networks fail — the cause depends on the symptom. The linked guide covers the Wi-Fi toggle and Forget This Network, plist file reset, DNS changes (Cloudflare 1.1.1.1 / Google 8.8.8.8), Wireless Diagnostics, VPN/proxy interference, WPA2 Enterprise / 802.1X troubleshooting in Keychain Access, and SMC/NVRAM resets on Intel Mac. Both Apple Silicon (M1/M2/M3/M4) and Intel Macs are covered.
How to Fix Mac Not Connecting to Wi-Fi | Password, Connection, and Speed Diagnosis
External HDD Not Recognized
If your USB / USB-C / Thunderbolt external drive doesn't appear in Finder, isn't even visible in Disk Utility, mounts only intermittently, or won't read a disk formatted on Windows — the diagnosis is split across hardware (cable, port, power), filesystem (APFS / HFS+ / exFAT / NTFS), and macOS permissions. The linked guide walks through the cable and port checks, Disk Utility's First Aid and manual mount, terminal commands like diskutil, NTFS workarounds, Privacy and Security permissions, SMC/NVRAM resets (Intel Mac), Safe Mode, and decisions about data recovery software vs. professional services.
How to Fix an External HDD Not Recognized on Mac | USB, USB-C, Power, and Format Diagnosis
Character Encoding Issues (Mojibake)
If text files from Windows show garbled characters, ZIP archives mangle Japanese filenames, PDF copy-paste produces unreadable strings, email content is corrupted, or your terminal can't display Japanese — the root cause is almost always a character encoding mismatch (UTF-8 vs. Shift_JIS / CP932). The linked guide explains the encoding mechanism, then covers fixes by file type: text files (CotEditor, VS Code), ZIP archives (The Unarchiver), PDFs, email, terminal LANG settings, Office for Mac CSV pitfalls, browser overrides, and missing-font tofu boxes.
How to Fix Character Encoding Issues (Mojibake) on Mac | Text, ZIP, PDF, and Email Diagnosis
Login Issues
If your password is rejected with the screen shaking, you're stuck in a login loop, FileVault won't accept your password, the Apple ID prompt fails, or you can't sign in after a macOS update — the cause splits across keyboard layout issues, FileVault and Apple ID desync, login-item conflicts, and (for business users) MDM authentication blocks. The linked guide walks through password basics, Apple ID-based reset, FileVault recovery key, macOS Recovery resetpassword, Safe Mode for login loops, MDM scenarios, and final data-rescue paths via Target Disk Mode and Mac Sharing Mode. Both Apple Silicon (M1/M2/M3/M4) and Intel Macs are covered. If your screen stays black with no login prompt, see the Black Screen guide instead.
How to Fix Mac Login Issues | Password, FileVault, and Apple ID Diagnosis
