  We analyze the primordial protogalactic gas to investigate the role of
thermal instabilities in the formation of condensations that could contribute
to the MACHO mass function. We find that the previrialized protogalaxy could
have undergone a thermally unstable regime which defines a peak in mass
condensations starting around $0.1 \, M_{\odot}$ after being reprocessed by the
environment which may be identified as giving origin to the MACHOs. Effects of
magnetic fields on this instability-driven MACHOs scenario are also addressed.
