I'm just responding to a few minor issues, quoted. > \[reporting file size\] 148,992 fileio.dll<br> Larry, I'd be interested to know how the size compares with the size of your FILEIO.DLL. I get your size with latest VS2019 compiler targeting x86 and 178688 bytes targeting amd64. > <b>Step 1</b> Start Command Prompt as Administrator That is not necessary. Ordinary privilege is all that is needed. > <b>Step 2</b> ... <b>Step 3</b> ... There is a VS2019 (and earlier) installation option to provide Start menu shortcuts that accomplish all that with two clicks and some mouse motion. > ... need to tidy up ... Deleted FILEIO.* It is odd to delete fileio.c and no other sources. > ... Tested FILEIO.DLL from my preferred location with success. I was unable to discover how that fileio.dll you found was built when I perused the site where you were told to find it. This makes me wonder what it really was. > Hopefully, this experience will save me (& others) time when compiling other extensions. Most (or maybe all) other extensions are as easy to build as is suggested at [Compiling a Loadable Extension](https://sqlite.org/loadext.html#build). I will ponder how to warn about the extra considerations for fileio.c when built for WIN32. > thank you You're welcome. We intend that this is somewhat easier than you experienced.