Apple fault codes and warning indicators, with meanings, causes, and step-by-step fixes.
39 models · 10 error codes
On Apple devices, Error 4013 means the iPhone could not be restored or updated because the connection to the computer was lost mid-process — often a cable/USB or hardware issue.
On Apple devices, Error 4014 means the restore/update failed due to a communication problem between the iPhone and computer — closely related to error 4013.
On Apple devices, Error 9 means the device disconnected from the computer during the restore, or a security-check failed — frequently a USB/cable or hardware issue.
On Apple devices, Error 14 means a USB connection or corrupted-firmware error interrupted the restore/update.
On Apple devices, Error 4005 means the restore failed due to a connection interruption — in the same family as 4013/4014.
On Apple devices, Error 3194 means iTunes couldn't contact Apple's firmware-signing server to verify the update/restore.
On Apple devices, Error 21 means the restore failed during the DFU/recovery process, often linked to a USB, security-software, or battery/hardware issue.
On Apple devices, Error 53 means a security/hardware validation failed — historically tied to a Touch ID (fingerprint sensor) or related component that no longer matches the device.
On Apple devices, Error 4000 means iTunes/Finder could not update or restore the iPhone, typically because it couldn't connect to the device properly.
On Apple devices, Error 1 means the restore failed at a low level — often because the requested iOS isn't compatible/signed, or a baseband/hardware issue on cellular models.
These codes apply across Apple models, including:
