When I hit C-x b to switch to buffer I receive:

Symbol's function definition is void: help--symbol-class.

I'm on Linux with Emacs 27.1 (build 1 - GTK 3.24.24)

  • 2
    Does it happen from emacs -Q? If not, I suggest you figure out what command you have bound to C-x b by typing C-h k C-x b. Aug 3, 2023 at 10:53

1 Answer 1


The help--symbol-class function is a standard part of Emacs, but only since version 28.1, so you evidentially have code in your config which is incompatible with the version of Emacs you're using.

I suspect you're using some package which purports to be compatible with 27.1 but has inadvertently introduced some code which depends on newer versions. (And is explicitly calling a function which, by naming convention, isn't intended to be part of the API; but maybe there was no better alternative.)

M-x toggle-debug-on-error should track down the culprit.

(If you don't know how to proceed after triggering the debugger, then copy and paste the backtrace into your question.)


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