  Weak emission line quasars are a rare and puzzling group of objects. In this
paper we present one more object of this class found in the Sloan Digital Sky
Survey (SDSS). The quasar SDSS J094533.99+100950.1, lying at z = 1.66, has
practically no C IV emission line, a red continuum very similar to the second
steepest of the quasar composite spectra of Richards et al., is not strongly
affected by absorption and the Mg II line, although relatively weak, is strong
enough to measure the black hole mass. The Eddington ratio in this object is
about 0.45, and the line properties are not consistent with the trends expected
at high accretion rates. We propose that the most probable explanation of the
line properties in this object, and perhaps in all weak emission line quasars,
is that the quasar activity has just started. A disk wind is freshly launched
so the low ionization lines which form close to the disk surface are already
observed but the wind has not yet reached the regions where high ionization
lines or narrow line components are formed. The relatively high occurrence of
such a phenomenon may additionally indicate that the quasar active phase
consists of several sub-phases, each starting with a fresh build-up of the
Broad Line Region.
