Sage currently doesn't provide a Sage 50 Accounting version for the Mac platform.
You can use Parallels to install Sage 50 on a Mac. However, Sage hasn't done extensive testing of Sage 50 Accounting in such operating environments and is unable to support them.
CAUTION: Use of Sage 50 Accounting is at the sole risk of the user. Mac operating system isn't officially supported, and performance and functionality may be limited or unstable.
NOTE: Sage Accounting is an alternative cloud-based solution that works for Mac users and Windows users.