Start with these three steps
Record the exact screen
Photograph the symbol or error and note whether progress changes. Record any update, power interruption or drive replacement immediately before the failure.
Stop if storage seems unstable
Clicking, repeated disappearance, severe slowness or copy errors call for assessment. Avoid turning a single startup problem into hours of repeated restarts.
Identify the processor family
Use the iMac model to choose the correct Recovery route. Intel keyboard shortcuts and Apple silicon startup options are different.
Describe the failure before changing it
A question-mark folder, prohibited symbol, stalled progress bar and blank screen are separate observations in Apple’s startup guidance. Note which appears and whether macOS Recovery is available. Do not interpret every icon as proof that all data has disappeared.
For an otherwise stable machine, Intel Recovery commonly starts with Command-R; on Apple silicon, hold the power button to load startup options, then select Options. Use the instructions for the actual iMac. If the disk starts making abnormal sounds, stop regardless of which screen appears.
Sources: [1] Apple Support [2] Apple Support [3] Apple Support
Use available access to copy priority files
If normal startup fails but the machine remains stable, Intel target disk mode or Apple silicon Share Disk may expose files to another Mac. Use Apple’s model-appropriate cable and connection instructions; a cable fitting the port does not establish that it supports the required transfer.
Have a separate destination ready. Start with the files that cannot be replaced, then verify that copied documents open and videos play. Stop when repeated read errors or disconnections appear. These transfer modes do not overcome a failing disk or missing decryption credentials.
Sources: [4] Apple Support [3] Apple Support
Understand what First Aid changes
Disk Utility First Aid addresses formatting and directory-structure errors. Apple tells users to have a current backup first. It is not a physical repair for a clicking drive, and completing it does not prove that every required file is intact.
If the data is the only copy, arrange a preservation plan before repair attempts. Apple’s general troubleshooting can lead to erasing a disk that cannot be repaired. Stop at that decision: an erase may help reuse the device while destroying the data you came to recover.
Sources: [5] Apple Support
Keep firmware Revive and Restore distinct
Certain Apple silicon or T2 startup failures, including rare firmware problems after interrupted installation, may call for another Mac to revive the firmware. Apple says Revive does not erase the affected Mac. Restore erases it and returns it to factory settings.
If a technician proposes firmware work, state that the unbacked-up files matter and confirm which operation is intended. Do not approve Restore merely because Revive failed without reviewing the remaining data options.
Sources: [6] Apple Support
A realistic view of recovery
- Recovery opening successfully does not establish that the internal drive is healthy.
- A startup repair cannot recover files whose storage contents or necessary encryption keys have already been lost.
Your questions, answered
Can reinstalling macOS fix startup without losing files?
Should I keep running First Aid until it passes?
Will the Intel T-key method work on an Apple silicon iMac?
Need help with the original iMac?
Describe the model, what happened and which data matters. Data Recovery Lab NZ is an external specialist; ask it to confirm the assessment route for your exact device.
Sources & further reading
Primary and specialist guidance checked 27 October 2026. Features and instructions depend on the model and operating system.