Hi I'm still stuck with also providing my lecture notes as epub in addtion to its PDF version. The last year, when I tried figure what is wrong, Hans indicated a tool, a program, which allows to verify that that all start* stop* tag pairs are symmetric and placed in correct order. I just cant remember how it is called. Can anybody help here? Second are there any limits in how large files exproted to XML, XHTML etc can be. Does the exporter automatically try to split huge documents into multiple exported documents when some size is exceeded or was or is such a feature allways experiemental up to mkIV and what could break proper slitting which contexts, commands should not be active to avoid breakage. My current setup is neither a fresh install of latest standalone nor texlive installation. This task is still pending. I just have done some partial update mixing 2020 Texlife with 2021 standlalone by calling update.sh. So the aborting of the export in the middle of a hundred pages long document with plenty of floats and the heavy use of Aditya's t-vim package might additionally be worsened by some inconsistencies of my currently not clean installation. But to rule out or properly tackle down I think I believe knowing about possible Limitations of exporter in mkIV if any to be saving a lot of time The abort in xml export also occurs when i inline all files exempt t- vim code snippets, png or svg files replacing meta post images into one huge document removing any \input commands. Therefore i want to check first on the inlined document if there would by any asymetric start* stop* before persuing further.