After the latest MiKTeX update, I started getting "Missing delimiter (. inserted)." errors on places where I've never had such before. A somewhat minimal .tex file points the problem to physics.sty. Here is it:


% Bibliography/References:
\usepackage[nottoc]{tocbibind} % puts bibliography in ToC

% Language settings for special characters:

% enumeration and items:

% page numbering:

% mathematical packages:
\usepackage{mathrsfs} % additional caligraphic font for math
\usepackage{tikz-cd} % for commutative diagrams
\tikzcdset{arrow style=tikz,>=angle 60} 

        \exp(T)=\sum_{k=0}^\infty \frac{T^k}{k!}\in K[[T]]

This produces the error:

physics.sty error line 34: Missing delimiter (. inserted). \exp(T)
physics.sty error line 34: Missing delimiter (. inserted). \exp(T)

How do I fix this?


EDIT: Here is the entire log: http://pastebin.com/S80vDD7J

  • 1
    Erh according to ctan, the physics package was last updated in 2012. When was the last time you updated miktex? Also it might be an idea to also post the entire log file
    – daleif
    Commented Mar 7, 2017 at 18:32
  • @daleif: hi and thanks for your reply. Actually, the last time I updated MiKTeX (aside from today) was roughly a month ago, so not that long ago :) Things still weren't broken. But I guess I should have known better. I will include the full log ASAP.
    – M.G.
    Commented Mar 7, 2017 at 19:07
  • Also did you update both user and admin?
    – daleif
    Commented Mar 7, 2017 at 19:08
  • @daleif: I updated only as admin as I have the bad habit of logging as admin in windows... Now that I've checked again, the above seems to be the entire log in TeXstudio. Is there a "fuller" log? BTW, I've also made sure to synchronize the package manager, just in case that was the problem, but it wasn't.
    – M.G.
    Commented Mar 7, 2017 at 19:15
  • 1
    This is to do with some changes in xparse (used by physics): we are likely to update CTAN shortly to address them at present but I would urge you not to use physics: it is not really using xparse in the way intended.
    – Joseph Wright
    Commented Mar 7, 2017 at 19:26

1 Answer 1


This is caused by some changes in xparse, used by physics. Essentailly, physics (and some other packages) have used 'document commands' in a way that the team did not expect (nor intend to support). We will be issuing an xparse update shortly to fix the issue whilst we decide on a long-term policy. Once that happens it's likely that the team will explicitly rule out certain use cases, at which point physics will need an update.

  • Thanks for your input! I hope I am not being indiscreet if I ask you whether there is a rough time table when this xparse update will be released?
    – M.G.
    Commented Mar 7, 2017 at 19:42
  • @July Just working out a few details: CTAN probably tonight into TeX Live by Thursday and MiKTeX probably within a week,
    – Joseph Wright
    Commented Mar 7, 2017 at 19:44
  • Oh, that is much quicker than I expected to hear! Sounds great and thanks again! That settles it then, at least in the short term.
    – M.G.
    Commented Mar 7, 2017 at 19:47

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