What is MobileFileIntegrity?

MobileFileIntegrity is a key security process despite the "Mobile" in its name.

What is MobileFileIntegrity?

MobileFileIntegrity (also known as AMFI) enforces code signing and entitlement rules on macOS. It checks that every piece of code running on your Mac is properly signed and holds only the permissions it is allowed to use.

Why is it called "Mobile"?

The framework started on iOS (where code signing is strictly enforced) and was later brought to macOS as Apple tightened its security model. Despite the name, it is fully active on macOS.

What does it enforce?

MobileFileIntegrity checks:

• Whether code signatures are valid for all running processes
• Whether entitlement claims are genuine (is this app truly allowed the powers it claims?)
• Library validation (stopping unsigned libraries from loading into signed processes)
• Debugging limits (blocking unauthorised process inspection)

What happens if a check fails?

If MobileFileIntegrity finds that code is wrongly signed or claims permissions it should not have, the system can:

• Refuse to launch the process
• Kill the running process
• Block certain operations
• Log the breach

Does it affect developers?

Yes. Developers need to sign their code and declare entitlements properly. Ad-hoc signing and development certificates work during development, but the code must be signed.

Should you worry?

No. It is one of the most important security processes on macOS, guarding you against tampered or harmful code.

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