Creality Slicer 1.2.3 does not finish
Some STL models cannot be processed by the slicer - it just stop and does nothing. I have seen this problem for example with this thing: https://www.thingiverse.com/thing:2156108 . - I'm running Windows 10.
It may be that the model is too complex but as there is no error message it is hard to tell.
I have switched to Slic3r for this particular model and that worked.