client: Keybase.app stops at 'Loading...' on macOS Sierra (Installer crash on /keybase create)

After upgrading to the most recent Keybase.app version, the .app wouldn’t start, being stuck showing ‘Loading…’. The least bad workaround I’ve found so far is running keybase install on the command-line, which seems to be nudging things enough in the background to bump the .app past the stuck ‘Loading…’ message.

keybase install seems to run normally, except for this message: ▶ ERROR Error installing mount directory: signal: trace/BPT trap

my log id: 315fba62b9c26e2068c6de1c