Hi Warren and thanks; I get what you're saying. I am embedding the sqlite 3.28.0 C amalgamation in a custom build of db library used by my non-C application, and I've got all of these open for editing for debugging purposes. i.e. I am calling the C api, but I wasn't the author of all of the code involved. So... somewhere in between black-box non-C bindings and actually writing a C/C++ program. I assume the problem is not a sqlite problem (speaking of finger-pointing) and more of an "I'm not using it right problem", and was hoping it was a common user/developer error other than the nfs issue we were all thoroughly warned about — I'll spare everyone the fstab, but the database in question is 100% on an ext4 volume on an Ubuntu host and not on nfs; :) the database for [my optimize+WAL issue](https://sqlite.org/forum/forumpost/ab37b8ed32) is 100% on an apfs volume on a macOS host. Or hoping that there might be something more I can do to get more details back from sqlite; beyond calling `sqlite3_extended_errcode`, which still doesn't seem to giving me anything more than `SQLITE_IOERR` when the issue occurs. So, in summary: I'll try to minimize better, ideally reproducing in C or via the sqlite3 shell, but if someone thinks of anything in the mean time <3 Would you recommend that I reply to this thread with those, or do threads tend to die quickly and I should open a new one? Do people ever submit relevant db files? Thanks again, Arya