I've created a number of spreadsheets in previous versions of Excel that
employ named ranges with the format "Jnnnnnn" (where "nnnnnn" is a six-digit
number). This is now a valid cell address for things way down in the 10th
column. When I saved the workbook in the new XLSX format, Excel tried to
change all references to such names as "_Jnnnnnnn", but didn't change the
"Named Range" names accordingly -- my thousands (literally) of
formerly-working formulas all recalculated to "#REF". I've also got tons of
other workbooks that use link to these named ranges, which also now don't
work.

Is there a way to globally change the names of named ranges, in a manner
similar (or not) to the global search/replace function for actual cell
contents?