How remove tags from IDML files with the CleanUp Tasks plugin

Question

The SDLXLIFF version of an IDML file contains lots of redundant character format tags that I'd like to remove from the source and target segments.

I used the following search string:
<cf style="\$ID/\[No character style\]" nfa="true">(.*?)</cf>
and $1 as the replacement. However, when I run the CleanUp task plugin, I get multiple "Search text is empty" warnings and at the very end "Object reference not set to an instance of an object."

Lydia Simplicio · Answer

Hans Kröger Apologies for the delay in replying. What would help speed support up is if I could have an example file to play with. Is that possible? 
 Lyds

RWS AppStore > 2. RWS AppStore Applications

How remove <cf> tags from IDML files with the CleanUp Tasks plugin