hi guys, i generally use this file to test if math is "working", with the recent update i get a lot of errors such as; ! Missing number, treated as zero. <to be read again> $ \@@dobig ...o #1\bodyfontsize {}\right .\n@space $ }} \@mt@defaultBigl ...\puremathcomm {open}{\Big {#1} } l.99 \pauli = \dirac^2 = \Bigl( \sum_{j=1}^2 \sigma_j\big(-i\PD{}{x^j}-a_j\bi... ? with texlive 2008 it works just fine, i've attached the output of the TL2008. i'm certain that the same file was compiling just fine with (i think) luatex 0.31 (or pre 0.31). the content is from Mikael Persson's thesis. Mohamed