Two things might have gone wrong:
- the app is quarantined by Gatekeeper because it's from an unknown developer;
- the executable inside the app might have lost its execute permission during unzipping
To check quarantine, start Terminal and type "xattr " without the quotes at the prompt and drag the TheTwist049MAC app into the Terminal window. Terminal will fill out the path for you. Mind there is a space between the command and said path. Hit enter. If you see
com.apple.quarantine in the results, the app is quarantined.
To remove the quarantine, type "xattr -dr com.apple.quarantine " and drag the app again into the window. Again, mind the space between the command and the path. Hit enter. Quarantine should now be removed.
To check the second case, you need to look into the contents of the app: right click on TheTwist049MAC app, pick Show package contents. Navigate to /Contents/MacOS/. Inside that folder you'll see a file TheTwist049MAC. That file should be a Unix executable. If it's anything else, it has lost its execute permission.
To fix this, start Terminal and type "chmod a+x " without the quotes at the prompt and drag the file inside the Terminal window. Terminal will fill out the path for you. Again mind there is a space between the command and the path. Hit enter. The file should now be executable.
As a general precaution, make a duplicate of the app first before changing its attributes or permissions.
