# How to enable and view diagnostic logs

Should it happen that GrandPerspective crashes or hangs while scanning, then it is useful to view detailed logs in order to analyze the problem. This can be done as follows:

1. View log messages generated by GrandPerspective. In a Terminal window, use the `log` command to start monitoring GrandPerspective logs:
   `log stream --predicate '(subsystem="net.sf.grandperspectiv")' --level=debug --style=compact`
2. Next, start GrandPerspective with full logging enabled. To do so, start the application from another Terminal window using the `open` command with `-logAll YES` as commandline argument.
   For example, when you installed GrandPerspective in your Applications folder type:
   `open /Applications/GrandPerspective.app --args -logAll YES`
   Note: When you enable the "logAll" setting, potentially private information (the names of folders that are scanned) is logged. As these messages are classified as "debug", they are not persisted which reduces privacy risks. Nevertheless, it is highly recommended for privacy protection and improved scan performance to only enable full logging when needed.
3. Try to reproduce the problem you experienced.
4. Analyze the logs to see if the problem is reproducible and always occurs when scanning the same folder.