When you delete a file, it is moved to the trash bin and will stay there for seven days as default. You can change how long you would like files to stay in the trash bin. Go to the Preferences menu under Preset Account Settings. Here you can modify how many days the files shall be in the trash bin, and you can also empty the trash bin. It can take up to 30min before you can see storage indication go down. Please be patience:)

You will see that the files that have been deleted with auto delete have the option to be restored until the trash cycle has been run.
Auto-delete files are unaffected if you run the "Empty trash now" button and will only be deleted after the "x" of days the trash setting is set to before they are 100% deleted.
Auto-delete files are unaffected if you run the "Empty trash now" button and will only be deleted after the "x" of days the trash setting is set to before they are 100% deleted.
