@Magnum-Opus
Your search term *\\EngramEntry_ doesn’t work because you used the quantifier * without a preceeding character to define the character(s) the quantifier should operate on.
Because you want to match any characters before \EngramEntry_ you have to insert . which means an arbitrary character. This results in the search term:
.*\\EngramEntry_.
BUT your replacement string OverrideNamedEngramEntries=(EngramClassName="EngramEntry_ isn’t error-free as well. You need to escape the ( character because it’s a meta character in regular expressions. Thus your replacement string should be:
OverrideNamedEngramEntries=\(EngramClassName="EngramEntry_
If you would like to read a really good regular expression manual visit this site. At some points in the manual you have to know the exact flavour of regular expressions used at your site. Notepad++ uses the boost lib regex flavour.