Nonexistent Spamassassin User_prefs

This is for those who combine Spamassassin, Exim and Debian-spamd, and wish to fix those nonexistent spamassassin user_prefs: "No such file or directory" errors and others.

For others who see these error messages in /var/log/mail.log:

config: cannot create user preferences file /nonexistent/.spamassassin/user_prefs: No such file or directory
spamd[1305]: bayes: cannot open bayes databases /var/lib/spamassassin/bayes_* R/O: tie failed: Permission denied
pyzor: internal error, python traceback seen in response: Traceback (most recent call last):

This means you need to check your exim4.conf. You might still have this in your acl section

spam = nobody

if you replace this by (something like):

spam = debian-spamd

and restart exim4, those errors will likely be gone. Instead you'll see:

spamd: setuid to debian-spamd succeeded