I've just updated my TL2022 installation. It didn't go quite as smoothly as I would have liked (I think due to tlmgr getting confused between the system installation and the one that I was updating). Now expl3.sty is causing problems, specifically:


! LaTeX3 Error: Mismatched LaTeX support files detected.
(LaTeX3)        Loading 'expl3.sty' aborted!
(LaTeX3)        The L3 programming layer in the LaTeX format
(LaTeX3)        is dated 2022-05-04, but in your TeX tree the files require
(LaTeX3)        at least 2022-09-28.

For immediate help type H <return>.
l.77      \ExplLoaderFileDate{expl3.sty}}

Now, I suspect that nothing should be loading expl3.sty anymore since it is part of the kernel. But surely with the number of packages around that probably do still load it explicitly then having it in the format would register it as loaded so nothing else would do so?

Regardless, what is going on and how do I make it stop?

  • 1
    typically it means that you have a local format somewhere (or like me you have to many development versions ...) Commented Oct 20, 2022 at 21:38
  • @UlrikeFischer What file do I look for? Commented Oct 20, 2022 at 21:39
  • 1
    github.com/latex3/latex3/issues/811 Commented Oct 20, 2022 at 21:42
  • @UlrikeFischer Thank you! The fmtutil-sys --all has fixed this problem (and the other one too). Not sure if it's worth an answer or just close/delete the question(s). Commented Oct 20, 2022 at 21:48
  • 4
    I’m voting to close this question because the issue was specific to the (possibly flawed) OP's installation.
    – egreg
    Commented Oct 21, 2022 at 6:57

1 Answer 1


As Ulrike hints in the comments, the problem was that the formats hadn't been compiled properly - most likely due to tlmgr getting confused between different installations of TeXLive during the update and calling the wrong version of subprograms. Simply re-running tlmgr upgrade --all didn't re-run those subprograms as it didn't think it needed to, so I had to manually run fmtutil-sys --all and that fixed the problem.

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