It has something to do with the RegEx details. Consider the following 2 simple examples:
The following works fine (file is renamed):
Old Name: ([.])(.*)
New Name: \1_A_C.txt
C:\Temp[1]C.txt => C:\Temp[1]_A_C.txt
The following generates the error:
Old Name: ([.])(.*)
New Name: \1_A_\2
C:\Temp[1]C.txt => C:\Temp[1]_A_C.tx
Thus, for me, the "\2" in "\1_A_\2" causes an issue... !??
p.s. I am still perplexed about my original question about using a "?" wildcard in Standard Rename? Jon didn't respond to this. Were you able to reproduce it?
I'm stumped by this as all the regex does is generate the new name and you can see that's being done correctly in the Preview. Once the name has been generated, regardless of method, it's then passed to the same code to do the actual renaming.
[quote="leo"]
Which version of Opus are you using?[/quote]
It turned out to be a bug in the version I was using . When I tried version 9.1.3 everything worked fine....