Fix “exit status 1” / “Compilation error: exit status 1”

What you see

sketch.ino: In function 'void setup()':
sketch.ino:8:3: error: expected ';' before 'pinMode'
    8 |   pinMode(2, OUTPUT);
      |   ^~~~~~~
exit status 1

Compilation error: exit status 1

sketch.ino: In function 'void setup()':
sketch.ino:8:3: error: expected ';' before 'pinMode'
    8 |   pinMode(2, OUTPUT);
      |   ^~~~~~~
exit status 1

Compilation error: exit status 1

Quick fix — try in order

1. 1

   Scroll up to the first “error:” line

   Enable File → Preferences → “Show verbose output during compile” only if needed; usually the first red “error:” line above “exit status 1” is the real problem.

   Tried it
2. 2

   Fix the first error first

   One mistake (a missing ; or }) can cause dozens of follow-on errors. Fix the first, compile again.

   Tried it
3. 3

   Check the line before the reported one

   “expected ';' before X” usually means the semicolon is missing at the end of the previous line.

   Tried it
4. 4

   Look up the specific message

   Common ones: was not declared in this scope, No such file or directory, does not name a type.

   Tried it

Why it happens