Michal, Thanks for your reply. I will try the debug option.
With respect to a minimal example, on my machine the file below gives this error. jim@millstone:~/src/tmp$ make4ht jhtest.tex [STATUS] make4ht: Conversion started [STATUS] make4ht: Input file: jhtest.tex [ERROR] htlatex: Compilation errors in the htlatex run [ERROR] htlatex: Filename Line Message [ERROR] htlatex: ./jhtest.tex 6 Package biblatex Error: Patching 'endnotes' package failed. [ERROR] htlatex: Compilation errors in the htlatex run [ERROR] htlatex: Filename Line Message [ERROR] htlatex: ./jhtest.tex 6 Package biblatex Error: Patching 'endnotes' package failed. [ERROR] htlatex: Compilation errors in the htlatex run [ERROR] htlatex: Filename Line Message [ERROR] htlatex: ./jhtest.tex 6 Package biblatex Error: Patching 'endnotes' package failed. [STATUS] make4ht: Conversion finished jim@millstone:~/src/tmp$ I have this year's TeX Live (not the Ubuntu version, the download it from the home site version), which I updated yesterday. Thanks, Jim ................................................ \documentclass{article} \usepackage{biblatex} \usepackage{endnotes} \usepackage{lipsum} \begin{document} \lipsum[1] \end{document} ------------------------------- You can’t write tears Jimmy. -- Sean Lock ________________________________________ From: Michal Hoftich <michal....@gmail.com> Sent: Monday, October 24, 2022 8:38 To: Hefferon, Jim S. Cc: tex4ht@tug.org Subject: Re: [tex4ht] Advice on where to start? ⚠ External Sender ⚠ Hi Jim, > Thank you for the information, Karl. I'm certainly expecting some debugging > but I was at a loss as to where to dig in. > The tutorial is still incomplete, unfortunately. There is some information about debugging here: https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.kodymirus.cz%2Ftex4ht-doc%2FFAQandTroubleshooting.html%23faq-and-troubleshooting&data=05%7C01%7Cjhefferon%40smcvt.edu%7Cfd673b21c9a04879655808dab5bcbb7e%7Ccba7935edf564a6e9e66e8b9adbfaba4%7C0%7C0%7C638022119451885347%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=31WxdMRFySer%2FbosgYB%2F%2FUKmPnHDp05aIq%2BWHUjqt1w%3D&reserved=0 As Karl and Nasser said, you can try this command $ make4ht -a debug -m draft book.tex It should stop on errors and print the full terminal output. I think that in your case, the issue is caused by some package. I can see a clash between BibLaTeX and Endnotes, which I can confirm happens, and I will try to fix that. But there must be also some other issue, as it shouldn't result in a fatal error. Could you make a MWE that produces this fatal error a post it here? Best regards, Michal