Actually, I realized though that even though the client was appearing
frozen, by pressing several times on "i" (ten times also), it eventually
closes the resolve clock stuff and let me play with emacs like nothing
happened. Then, I can run manually M-x org-resolve-clocks in case I
wanted to really resolve the clocks (using k or g or whathever).
Even if this is an ugly workaround, I Hope that will help :-).
Thanks for the tip, I'll try pressing 10 times the next time it happens (which is probably today).