- a HDD may not work until it has been defragmented
- to fix bugs and errors in code
- in software development to optimize for a release candidate
- compatibility and configuration tweaking after OS or Service Pack upgrades
- to meet standards, verify data, theory, etc
- after hardware modifications, such as setting up partitions or device additions.
- detection and protection from scumware, exploits and other vulnerabilities.
A FAQ or HOWTO can provide useful knowledge to solve these sort of problems. Real-time information can assist monitoring problems until resolution and it helps to be logical when dealing with these machine performance problems.