@M-Andre-Z-Eckenrode said: For what it’s worth, I asked my brother, whom I know also uses Notepad++, to indulge me by repeating my Search++ regex experiments on his own computer, and he kindly did so after encountering some initial problems getting Search++ to work at all (see below for details of that). Anyway, he used a fresh portable copy with the latest versions of both, as I have, and reports getting one anomalous replacement while stepping through a text field made up of 11 copies of my recently reported example text. I think that duplicating the problem almost invariably requires many matches and replacement attempts, since it’s so hit or miss for whatever reason. Thank you, and thanks to your brother! Is he also using 32-bit Notepad++? About my brother’s initial failures to get Search++ to load in his portable copy: His first four or so tries were attempted in different virtual machines on his computer, including the very first one being Windows 11’s built-in “Sandbox”. All of them failed with messages such as “The specified module could not be found” and “Search++.dll is not compatible with the current version of Notepad++”. But when he tried the same set of files on his real machine, it worked. He routinely runs various other programs in virtual machines just fine. I just tried the same thing in Windows 10 Sandbox on my system and it also failed, with the same message. I will have to investigate that. Off the top of my head, I don’t know why that would happen. My guess (that’s all it is for now) is there’s some sort of C++ runtime dependency that nearly everyone has installed on their main machines, but that doesn’t carry over automatically to a virtual machine or a sandbox.