Thanks for the info!

Its been more than a decade since I worked on a serious Windows installation program for a huge 24/7 application. I am sure that my recollections are fuzzy from Perl 5.6, Win NT days! I remember spending a lot of time dealing with some of the more unusual cases, like what happens if we have a new fileA, but currently running processes are linked to an old .dll version or have open the old version of fileA or are using the info from the old version even though they have closed their filehandle to the old file version. That kind of system coordination stuff can be a mess and beyond the scope in this thread.

The general advice in this thread:

1. Get the new copy "ready to go" on the HD.
2. Make a backup of the original file and have a plan to revert to that if something fails.
3. Do the file replacement (newFile replaces oldFile) in the fewest, fastest steps possible.

Are fundamentally sound, excellent practical advice.