How to remove apostrophes from search query w/ $regexp?

You may try this formatstring ...

$regexp(%ALBUM%,'(\s+\[.+\]$)|\x27|'$regexp('-_.+!(){}[]^$~*?,:\','.','|\\\\$0'),,1)

... or ...

$regexp(%ALBUM%,'(\s+\[.+\]$)|\x27|[^\w\s]',,1)

DD.20160404.2306.CEST