I've attempted this run in three different PCs (Windows 8 and 10) and on two IQTREE versions (1.6.4 and 1.6.7.1) and get the same issue everytime.
Command line is: iqtree -s data.nex -spp partitions.nex -bb 1000 --runs 10
The moment it starts running MF, it crashes and IQTREE is forced to close.
Seed number: 127001
The last log files are (there is no ERROR message):
Create initial parsimony tree by phylogenetic likelihood library (PLL)... 0.024 seconds
NOTE: ModelFinder requires 13 MB RAM!
Testing GTR+F+G on supermatrix...
GTR+F+G4 / LnL: -17971.561 / df: 142 / AIC: 36227.122 / AICc: 36290.381 / BIC: 36889.649
Selecting individual models for 2 charsets using BIC...
No. Model Score Charset
Thanks for the help!