SpamSieve reads your macOS address book in order to prevent marking messages as spam if they were sent by one of your known contacts. This is controlled by the Use macOS Contacts preference.
It also reads which e-mail addresses are yours, in order to detect spam messages that may have been forged to come from your own address. This is controlled by the Catch spam sent from my own addresses preference.
Access to Your Contacts
The first time you use SpamSieve to filter messages, it will ask for permission to access your contacts. You can change the access setting by opening System Settings, going to the Privacy & Security pane, clicking on the Privacy tab, clicking on Contacts in the list, and checking or unchecking SpamSieve.app. (Please note that the applications in the list are not sorted alphabetically.)
Normally, macOS will remember when you’ve given SpamSieve permission to access the contacts. If it keeps prompting you each time SpamSieve is launched, this is probably because you have modified your copy of the SpamSieve application, breaking its code signature. It is no longer necessary to modify SpamSieve to hide its Dock icon; please see the Show Dock icon section.
Repeated Access Prompts
If the system keeps asking you for permission to access your contacts and does not remember this between launches:
You may need to reset the privacy database by entering this command in Terminal:
tccutil reset AddressBook
Your copy of SpamSieve may be damaged. Please see the Reinstalling a Fresh Copy section.