this is just a status update, mostly for anyone in the future who might find this useful for their problem. but, if anyone in the near-present has any comment, i'm happy. (and, i appreciate all the help up to now!) presumably this is all fallout from some historic "npm update -g". way too many details follow. i removed all files from /usr/lib/node_modules/npm/node_modules *not* owned by the npm package. then, [pacman -Syu] (without '--overwrite', as the offending files have been removed)succeeded. but, in the output, immediately after ---- (192/192) checking available disk space ---- (and some trailing ###...) there were a number of lines like ---- warning: could not get file information for usr/lib/node_modules/npm/node_modules/meant/.npmignore warning: could not get file information for usr/lib/node_modules/npm/node_modules/meant/.travis.yml warning: could not get file information for usr/lib/node_modules/npm/node_modules/rc/node_modules/ warning: could not get file information for usr/lib/node_modules/npm/node_modules/rc/node_modules/minimist/ warning: could not get file information for usr/lib/node_modules/npm/node_modules/rc/node_modules/minimist/.travis.yml warning: could not get file information for usr/lib/node_modules/npm/node_modules/rc/node_modules/minimist/LICENSE warning: could not get file information for usr/lib/node_modules/npm/node_modules/rc/node_modules/minimist/example/ ---- [pacman -Qo] says they are all owned by no package. if that is so, what is causing the upgrade process to look for them? then, after those warnings (in case context is of use) ---- :: Running pre-transaction hooks... (1/2) Removing linux initcpios... (2/2) Unregistering Haskell modules... :: Processing package changes... ( 1/192) upgrading alsa-card-profiles ( 2/192) upgrading alsa-firmware ---- (with some trailing ###... on the last two lines). and, after a bit ---- (144/192) upgrading npm (145/192) upgrading npm-check-updates ---- (ditto) .../rc/package.json shows a dependency on minimist. [pacman -Qo] doesn't seem to know any of the warned-about files; and [pacman -Qkk npm] says "0 altered files" (ditto for [pacman -Qkk npm-check-updates]). (and, everything under /usr/lib/node_modules/npm/node_modules is owned by (the new) "npm 6.14.8-2". unfortunately, i did *not* run [pacman -Qkk npm] *before* doing [pacman -Syu]. cheers, again thanks, sorry for all the detail, Greg