I updated my packages in texlive 2021 today through the GUI package manager. Afterwards, no document compiles. When trying to compile a basic document with pdflatex, I receive the following error:


---! c:/Users/.../texlive/2021/texmf-var/web2c/pdftex/pdflatex.fmt made by different executable version (Fatal format file error; I'm stymied)

When compiling a basic document in xelatex with polyglossia, I receive the following error message:


! LaTeX3 Error: Mismatched LaTeX support files detected. (LaTeX3)
Loading 'expl3.sty' aborted! (LaTeX3) (LaTeX3) The L3 programming layer in the LaTeX format (LaTeX3) is dated 2021-06-01, but in your TeX tree the files require (LaTeX3) at least 2021-07-12.

Neither compilation produces a log file. Clearly something has gone very wrong, but I wouldn't know what. Any pointers?

  • 2
    Did you try fmtutil-sys --all to remake the formats?
    – Marijn
    Commented Aug 4, 2021 at 16:47
  • See also tex.stackexchange.com/questions/576918/….
    – Marijn
    Commented Aug 4, 2021 at 16:50
  • check if you have local formats around which interfere Commented Aug 4, 2021 at 16:51
  • 2
    well is it fixed? Commented Aug 4, 2021 at 17:47
  • 2
    The format files .fmt (like latex.fmt, xelatex.fmt and many others) contain a precompiled version of the respective kernels that is loaded automatically when compiling a document. Among other things expl3, which is frequently updated, is part of the kernel. When you update packages that depend on a .fmt file the versions must be in sync. Therefore after a package update that includes such packages the formats should be compiled again. See tex.stackexchange.com/questions/585664/… for more background.
    – Marijn
    Commented Aug 4, 2021 at 21:15


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