Can't activate

The problem is exactly what the error says: you’re missing the wp_relevanssi_stopwords table. For some reason it was not created when the plugin was installed.

Either try installing the plugin again, or take a look at lib/init.php for the table structure and create it manually.

Yes, for some reason installing and re-installing the plugin doesn’t make any changes.

I’ve tried:
a) Deactivating/re-activating the plugin.
b) Deactivating/deleting/install from repo/re-activating the plugin.
c) Deactivating/deleting/dropping database tables/install from repo/re-activating the plugin.

I’ve also tried installing it on another site on the same server, which is working perfectly well… Tables install first time and indexing works perfectly.

Does the plugin leave any other residual information except from the _relevanssi* tables and the plugin files? Wondering if there’s a block somewhere else.

There are options in wp_options table as well, but they shouldn’t cause problems. They all have names starting with relevanssi_, so it’s easy to swipe them away if necessary.

Does it work if you just create the table manually?