After installing new software on IMac and Macbook the App is not any longer to be started. I suppose it´s "El Capitan", will there be any help? Same problem of other users?

I've installed Parallels Desktop 11 and Windows 10 on my MacBook Pro and SkyDemon (Windows) works a treat.

I tried El Capitan but too many thinks do not work such as iPhoto which is now dead apparently and will not sync properly to iPad.  Gone back to Lion and everything is well. Like another user, I have an old laptop running W7 just for SkyDemon. I'm not sure even that is needed now as virtually everything can be done on iPad.  Perhaps I'm just a bit of a stick in the mud.