I got back to 4.3.0 meanwhile, where things are somewhat better. My earlier problem here was also solved completely by changing the compatibility mode to winXP. Now, in 4.3.0, Adria still "breaks" sometimes, but here at least restarting Adria has solved the problem every time for me.
So I continued my research there and this is what I found so far:
* When started, up, even when the OCR is turned on, everything works flawlessly.
* After the first item has been scanned, the mouse pointer becomes invisible when hovering over the Adria window. This remains until the OCR is turned off. No big deal on itself.
* After (succesfully) scanning 6 items, Adria "breaks". Specifically it somehow loses (at least part of) it's key hook, as even F12 doesn't work to start and stop the OCR -- and it's more severe than just the hook, as even when I put the focus on the Adria window, the F12 key still doesn't work to turn off the OCR (and when it's stopped, F12 doesn't turn it back on either). Here, the mouse bug I mentioned above also comes in very unhandy: due to the invisibility, it takes some trial&error to get the mouse pointer on the button to stop the OCR.
When the OCR is stopped, the mouse is back, even after breaking, but the keyboard (or at least the F12 button) remains dysfunctional. Adria remains broken until the application is closed and re-started. Interesting to note is that breaking seems to happen always after exactly 6
items. I don't know why, perhaps some cache that is full? Stopping and restarting the OCR inbetween items doesn't change this: after 6 items, Adria breaks. It is also not time-dependent: adding them fast or with a 10-second delay between them doesn't make a difference.
The above happens consistently to me (5 times in a row now). I hope this information helps you in debugging. If there's something else you want me to try, please let me know.