I'm the DBA and the Accpac guy is telling me we need a SQL login for the Accpac databases. Right now I use only Windows authentication, and I don't like the idea of turning on mixed authentication if I don't have to. So before I agree to it, I want to make sure it's necessary. Can Accpac use Windows logins?
You can use accpac 6 and windows authentication. you do not have to use both. your accpac server should be part of the domain in order for it to run more effectively
I am NOT sure how many folks are well versed with AccPac here and I have never heard of them until today. Your best bet is ask the AccPac guy to provide documentation (potentially from the company's manual) why only SQL authentication is preferred and the windows authentication.
From the website, it looks like they allow windows authentication too but not clear enough.
http://community.sageaccpac.com/blogs/r_and_d/archive/2011/03/05/diagnosing-problems-with-sage-erp-accpac-6-0a.aspx
You should use SQL login details for accpac for it to really work else you won't be able to access accpac database when there is trouble. More so, portal setup in accpac only accepts SQL login details so ensure you use mix mode authentication for your SQL.