[R-sig-ME] Fwd: Model failed to converge in bootMer

[Francisco Fabuel]

I'm trying to estimate some quantities derived from a lmer object using
bootstrap. When I use the function bootMer, a large proportion of
replications seems to fail to converge, but if I program the bootstrap
using package boot, everything seems go well.

Please, find attached a simple example (R script and data) of the problem:
with bootMer in 10 simulations, I've got 7 warnings:

Warning messages:1: In checkConv(attr(opt, "derivs"), opt$par, ctrl =
control$checkConv,  :
  Model failed to converge with max|grad| = 0.00132463 (tol = 0.001,
component 1)


Thank you in advance.
Francisco Fabuel