Note: Startup disk isn't accessible on macOS Big Sur 11, Catalina 10.15, Mojave 10.14, or High Sierra 10.13 from any third-party applications due to System Integrity Protection (SIP). This feature prevents any modification in the protected system files and folders on your Mac.
To scan startup disk on macOS Big Sur or earlier using the latest version of the software, you need to allow Stellar Data Recovery Extension from the software's interface. This extension is available in the Free, Standard, Professional, Premium, and Technician editions.
Now, you can perform Mac data recovery on your startup disk by using Stellar Data Recovery for Mac.
Note: If you've clicked OK on the System Extension Blocked message box, then you need to open the Security & Privacy window manually. Click the Apple icon and select System Preferences, then select Security & Privacy. Next, follow STEP 3 and STEP 4 as explained above.
It is necessary to temporarily disable System Integrity Protection (or SIP) on Mac to create a recovery drive. Follow the below steps:
Steps to Disable SIP Temporarily:
Restart macOS High Sierra, Mojave, Catalina or Big Sur. Go to the Apple logo on the top-left corner and click the Restart option.
Immediately press-hold Command + R keys simultaneously. Release the keys once you are in macOS Utilities.
In the Recovery Mode, Launch Terminal from Utilities menu. Now, enter the command csrutil disable.
Press Return to disable SIP. Restart macOS and launch Stellar Data Recovery software to create a recovery drive.
Once the task is done, boot into recovery mode and type csrutil enable, and press Return. This will enable the SIP.