Steps to Reproduce:

This is probably because now only 64bit apps are working
@deshi9012 My last comment was wrong..
There is a easy fix.
try to open it then go to
--> Settings
--> Security
there stands that it was blocked from starting. Here you can allow it
Oh yes, thank you! That was helpful, now it works!
I am unable to find the Settings Security in my MacBook Air. Can you please help me out to fix it MacBook Air.
@patelmurtuza - If you go to the System Preferences do you see a section for Security & Privacy? I don't have a Macbook air to check on myself unfortunately but it should hopefully be there
System Preferences --> Security & Privacy
ignore "Security" tab, go to "General"
Most helpful comment
@deshi9012 My last comment was wrong..
There is a easy fix.
try to open it then go to
--> Settings
--> Security
there stands that it was blocked from starting. Here you can allow it