Home / Unresponsive after word search multiple times

The first few times was fast and precise, and then suddenly it became unresponsive and crashes after I click Find Next too many times.

The file has to be big, though, like over 50 MB or something.

Best to report performance issues via sumatrapdfreader on GitHub and if you get a crash follow the instructions to upload the report there for a fix
Please confirm there exactly which version/variant/os you are using since there have been many past fixes.
However this does sound like Reduce pdf text search memory which is still open