Troubleshooting

Symptom → Cause → Fix patterns for the most common issues encountered when switching from Windows to Linux.

Fix broken APT repositories, expired keys, and conflicting PPA problems on Ubuntu 24.04-based systems.

Use journalctl, dmesg, and /var/log files to diagnose Linux issues — with real examples from one Ubuntu-based migration.

Recover access to your Linux Mint or Zorin OS account when you have forgotten your login password — via fingerprint shortcut or GRUB recovery mode — and fix the keyring mismatch that follows.

Fix low transmit power, authentication timeouts, and random disconnects on MediaTek MT7921e WiFi cards — tested on Ubuntu 24.04-based distros with a ThinkPad L14 Gen 2.