# Clean temporary files

The clean system action is used to remove temporary files used in the build:

## Temporary file types

- **Extract files** - Temporary files created whenever Designer extracts data from a database
- **Temporary files** - Temporary file created when Designer builds indexes or other files used for performing the data load, etc

Some temporary files can be re-used on subsequent builds if the incoming data has not changed, cleaning these files will reduce load performance in these cases.