Update: As of OS X 10.11 Public Beta 2, the compatibility issues described in this blog post have been resolved.
Today marks the beginning of Apple’s public beta for the next version of OS X: 10.11 “El Capitan”. In addition to the usual disclaimers that accompany beta-quality software, we want to point out to eager Direct Mail users that the current version of Direct Mail (4.1) is not compatible with the public beta of El Capitan (as of this writing). For our technically-inclined readers, beta 2 introduced a WebKit-related bug that is responsible for the crash. We have notified Apple of the issue (rdar://21690765) and hope they will have it resolved in an upcoming seed. In the unlikely case that the bug survives until the release of OS X 10.11, we have identified a workaround that will be ready in time.
Our recommendation is to not install the public beta of El Capitan on any Mac that you plan to use Direct Mail on—at least until we’ve confirmed that Apple has fixed the bug. As always, please contact our support team with any questions.