In this Appendix, we will go through various FAQs related to common troubleshooting issues. Although not every type of issue can be covered, we will provide answers and practical suggestions for solving the most common types of problems related to topics such as issues with apps, disks, volumes, and more; for example, what to do if you have problems with a specific app; and what to do if a disk shows unexpected behavior and seems to be corrupted; and so on.
The tools macOS provides and that will be frequently used for troubleshooting are the Console and the Activity Monitor apps. Both can be accessed from the /Applications/Utilities/ folder, though you can use Spotlight to locate them quickly.
Some of the suggestions ...