MacBook Air El Capitan Not Starting

[MontyC]

I am getting this error on startup.. After the message appears for a few seconds laptop turn off and tries to start again with the same error. Reset PRAM with no impact and tried a safe startup which doesn't seem to work.

Any ideas what I can do?

 

[keysofanxiety]

I am getting this error on startup.. After the message appears for a few seconds laptop turn off and tries to start again with the same error. Reset PRAM with no impact and tried a safe startup which doesn't seem to work.

Any ideas what I can do?

Hold CMD+R on startup to boot into OS X Utilities, try verify/repair disk. Any better?

 

[MontyC]

Repair worked. Many thanks for your help.