For years I have opened text files in Excel using the right-click
"Open With..." in Windows. The files opened without triggering the
Import Text Wizard and were imported in one column. As of yesterday
(without any apparent changes to Excel or Windows), this behavior
changed. Now when text files are opened using "Open With...", Excel
"figures out" where it thinks the columns breaks should be. (Again the
Import Text Wizard is not triggered opening files this way.)

I've searched for settings that determine how Excel opens text files
by default, but found none.

Any ideas on how to go back to right-click opening the "one-column"
text files?

Thank you,
Patrick