Delta Tao reports:

The v852 Mac client had an annoying auto-update bug, which we didn’t know about until an hour or two after the v855 storm. As a result, the first edition of the v855 Mac client contained the same bug too. The symptom is that the auto-update process stops midway through, after successfully downloading the replacement client but before firing it up.

If you haven’t yet been able to auto-upgrade your v852 client to v855, then look in the “Downloads” folder beside it. You’ll find a shiny new v855 client waiting there, all ready to go. Simply drag that out of “Downloads” into the enclosing folder, replacing the 852 client, and you should be all set. (See also the discussion of this issue on the Sentinel.)

If you did successfully upgrade from v852 to v855 soon after the Storm — in other words, earlier than approximately 1:00 AM EDT on 17 April, then you received the bad 855 client. You should download this repaired v855 version, which fixes the bug. Otherwise the v858 update (three weeks from now) won’t go as smoothly for you as it’s supposed to.

Sorry for the inconvenience.