AmberV – Yes! Thx.
(The ‘fonts only’ conversion removes the text’s non-standard color, leaves original line spacing.)
The keystroke sequence through the Document menu works fine with a file that is open in a Quick Reference window …
Because QR doesn’t have the Copy To option, Alt-D-C takes me straight to Convert. (Which I follow with … -D-Spacebar-Enter.)
However, in an editor window, the Document menu includes Copy To –
For me, this is a nuisance because I have that medium-sized project (word-corpus wise, but with 25k files) that we dealt with upgrading to Windows Scrivener v3 about a year ago. …
As then and continuing, anytime I activate a menu item that triggers a file list, Scrivener takes about 20 seconds (22+ just now) to complete its routine. (It is enough time for me to step into the kitchen and refresh my drink or peel a protein bar.)
My workaround is to invoke the Documents menu, then down arrow past the Copy To (and Move To); its pace being quick enough to not wake up the Copy/Move options as the selection passes.
My cursory troubleshooting for this suggested that the gross word-corpus size has little to do with v3’s snail-crawl file list options compared to v1’s (2-4 seconds), but perhaps as Katherine suggested a year ago, it could simply be the number of files involved.
Taking this possibility and from my four-project testing, large and small, I am consolidating files as I encounter opportunities.
Another aspect of my testing suggests the question: Could it be my extensive use of cross-links, including self-referential, that I use in the 25k file project? (The cross-links are ubiquitous, probably only in a few 100s of files?)
I am sorry for the digression, probably Too Much Info … but it has been a while since I’ve surfaced my ongoing avoidance of what are clearly useful tools.

Again, thank you for the document conversion pointer (and that earlier for text coloring).
