5. Troubleshooting (28%)

Troubleshooting is the highest-weighted domain on the exam for good reason—it's the domain that integrates everything. A troubleshooting scenario tests your hardware knowledge, your network knowledge, your OS knowledge, and your security knowledge simultaneously. You can't troubleshoot what you don't understand.

The exam presents troubleshooting as scenario-based questions: symptoms are given, causes are asked, or tools are asked about. Success requires two things: a systematic methodology (so you don't chase symptoms randomly) and domain knowledge deep enough to generate plausible hypotheses. This phase provides both.