Hmm, that sounds odd.
Are you able to complete the following for example (if not will need to talk to Petko about what could be causing the problem):
1. Symbol – EURUSD H1 50000 bars
2. Robustness – Monte Carlo only 80/20
3. Acceptance – complete: pf> 1.2, is: pf> 1.1, oos>1.1
Can you replace the info above with your values? Also how many calculations are being performed (the number right of the start button)?
I am almost positive that the issue of so few strategies in the collection is either an overly strict acceptance criteria, robustness check or a combination of them both.
The information on the reactor screen will show what the bottleneck is ie if you see after a few hours that you have 1000 EAs passed to Monte Carlo check but only 2 make it through that check to the collection then that is a problem with Monte Carlo.
Or perhaps you see that of the 200,000 calculations on 2 are making it through the acceptance criteria and then being passed to Monte Carlo, the you know your acceptance criteria is too strict.
Hope that makes sense and you get to the bottom of the issue soon? If not then let me know and there may be a couple of other things but this would be where I would start troubleshooting