1, wrong optimization setting: When using computer housekeeper to slim down drive C, some system files or startup items may be disabled or deleted due to misoperation. This may affect the normal loading when the system is started, resulting in a slow startup speed.

2. Excessive cleaning: If some important system files or startup items are cleaned during the slimming process of drive C, the system may not load normally at startup, thus affecting the startup speed.

3. Too many temporary files and caches: If there are still a large number of temporary files and caches occupying disk space after the slimming operation of drive C, it may affect the boot speed.