How Does Mac Recovery Work and is allowing Full Disk Access to an app a security risk?

My current online backup service expires on 9/2 and I do not want to renew that app. I was going to get iDrive - the 100GB plan will work for me, but then I saw that I can back up with OneDrive. I already have an MS356 subscription with 1TB on OneDrive (of which only 40 GB are being used).


OneDrive will only backup files and folders. Which I think, is fine. I have Time Machine, but if that were not available, for whatever reason, my understanding is that I can recover the Mac using this process How to start up from macOS Recovery - Apple Support


So I don’t need to have a full system backup System Files, OS, etc. iCloud has my apps. OneDrive would have my data. And Recovery would have the system/OS needed to reload, is my understanding correct?


The problem (for me) is that OneDrive requires Full Disk Access to enable backup. I don’t totally understand what access I would be allowing for OneDrive by enabling this. Is it a security issue? If so, I can get iDrive for backup. thanks!


Posted on Aug 19, 2025 04:30 PM

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6 replies

Aug 19, 2025 06:26 PM in response to donnafromme

Full disk access means access to everything including system configuration files.


Allow access to system configuration files - Apple Support


OneDrive requires that to backup your data.


IMO, OneDrive isn’t really a true backup solution. If all you care about are documents, syncing them with OneDrive will enable you to restore them if needed. But many things, e.g., settings, preferences, etc., won’t be backed up. Nor will data stored by apps in certain locations. You’ll probably run into files that aren’t backed up because macOS is less restrictive about file names. Lots of issues.


Time Machine backup to a local drive (preferably more than one, drives fail) enables you to literally pick up where you left off of you ever need to restore your Mac.

Aug 19, 2025 06:16 PM in response to donnafromme

Prior to macOS Mojave (10.14) there was no such thing as Full Disk Access. Every app had access to your entire system, period. You didn't have to grant permission.


Apple then began implementing more privacy & security features including Full Disk Access, which basically turned the tables 180º and walled off everything. Now you have to expressly give permission to apps to allow them to access yuor system.


Is it a security risk? No, not in the sense that you may be worried about. Giving FDA to OneDrive is necessary in order to enable it to backup your data; it will allow the backups to proceed and will not harm anything.

Aug 20, 2025 03:34 AM in response to MartinR

Well, the explanation about FDA make me feel better about allowing access, if I do give OneDrive access! ☺️

The explanation about how OneDrive backs up makes me think I do not want to use it, so they kind of cancel out using OneDrive for backup!! 🤣


I have Time Machine backup. I think it’s GREAT! I am always going back to check files and like the peace of mind knowing everything is backed up. But I need offsite backup - it’s best to have at least two backups one onsite, one offsite. Plus, Time Machine is hardware-based, which could fail. The other backup will be cloud. Either could fail, but two are better than one! thank you both for your help.

How Does Mac Recovery Work and is allowing Full Disk Access to an app a security risk?

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