The addon checkbox is greyed out
When Bookmap will not let you tick Norden Statistics, and what is and is not your install.
The symptom
You added the addon in Settings, Configure add-ons, it appears in the list, and the checkbox beside Norden Statistics will not tick. Bookmap may mention API modules not being allowed.
What it is
That is a Bookmap restriction, not a broken install. Bookmap decides which addons a given account and feed may run, and nothing you change on your own machine lifts it. You did not do anything wrong and reinstalling will not move it.
Tell us with a ticket about the addon and we will take it from there. Say which instrument you were on and which feed you are running, because the restriction is not the same on all of them.
Two things that look the same and are not
The box unticks itself after a restart. That is not the restriction. Bookmap remembers the file by its location, so if the addon file moved, or it is still sitting in Downloads, the entry goes stale. Move the file somewhere permanent, remove the old entry in Configure add-ons, and add it again from its new home.
The box is ticked and one instrument still records nothing. The tick is per instrument. If you trade ES and NQ, it has to be ticked on ES and on NQ. An instrument you forget records nothing and nothing warns you.
When a newer addon comes out, remove the old entry in Configure add-ons before adding the new one. Two entries for the same addon is its own kind of confusing.
What the addon records, and where
It records the market around your orders and your own orders. It records nothing from other applications and nothing at all while Bookmap is closed.
The recordings sit in a folder called NordenMarket in your home directory and delete themselves after two weeks.
To stop recording, untick the box. To take it out of Bookmap entirely, use Remove in Configure add-ons.