Baffling new (out of the blue) problem recording Addictive Drums

I appreciate the reply, but in this case I'm not using a keyboard as a midi trigger. I've always been able to record the beats that are contained in AD, or individual triggering of the kit pieces inside the plug in via the mouse simply by arming the track and hitting record, without making any other setting adjustments. I'm convinced there's some new conflict somewhere. It would almost make more sense if the track's meters didn't indicate that there's drum data being produced, yet the meters dance, the track is armed, the record button's hit, and nothing... Nevertheless, I'll push some more buttons based on your thoughts.

Sorry, I have no input to offer, but I am about to purchase Addictive Drums 2 and am interested in the outcome of your issue gm.

What about selecting : Record: input, audio or midi... Record: output, audio stereo... Do you get anything to record trying either / both of these ways? I am also still suspicous you have a midi channel mismatch issue. Look in the ad gui and see what channel it is set up to output from. (While you are at it what are all the options ad has for output? It outputs either midi or audio - maybe? - and it could have reset on you?) Inspect the midi notes that you are inputing from the midi editor that are playing by right clicking and looking at event properties for the midi channel of the notes. Do they match? Report back on those results and maybe it could help narrow down the issue.

So I just tried triggering AD with my Roland V drums, and recorded midi with no problem, so this is some relief. And I can pull down beats from AD, and they work. Up until moments ago, I was certain I had used the mouse to trigger the drums from the AD plug in, but I'll now concede there's a chance I didn't, and I may have used my Akai MPK225 (not currently connected) to trigger and record previously.

I may be missing the point here but anything might help ... I have AD set up as a VSTi on a track and I select either my midi keyboard or Akai MPD218 set to 'All midi channels' <-- I always do this as the Akai uses channel 10 or 20 or something. You said you "hit play on AD, and then hit record" (did you mean record in AD) <---I never do this. I choose a beat and drag it to the Reaper track. Arm the Reaper track. I have AD 'sync and play' enabled and all works. On my MPD218 or keyboard for finger playing, I select either my midi keyboard or Akai MPD218 set to 'All midi channels', choose the kit I want, arm the track in Reaper than hit record in reaper, do my inept finger thing - bobs your uncle, fanny's your aunt - done! When I am happy with the result I usually freeze the track or route it to another track as audio then, eventually, delete the AD track. Sorry if this is too simplistic, sucking eggs and all that...:)

Not too simplistic. Sometimes things have to be expressed very simply for clear communication. I contacted XLN customer support. They indicated that AD is not designed to have individual drums triggered from within an open AD plugin, so I was under a misconception. If I want to trigger AD, I have to use a midi device like an Akai MKP225 or my Roland V drums.