Microsoft Supports APFS External Drives for OneDrive on macOS: What You Need to Know

Mac users who have long struggled with managing large volumes of files between their device’s internal storage and external drives will be excited by a pivotal update from Microsoft: OneDrive for macOS now officially supports syncing files directly to APFS-formatted removable drives. This long-awaited feature eliminates a pain point for users juggling personal and business documents across multiple storage locations, providing much-needed flexibility and efficiency. The development also underscores Microsoft’s recognition of the Mac ecosystem’s storage realities, especially as solid-state drives grow cheaper and usage of portable drives surges among professionals and creatives.

OneDrive’s Evolution and the Storage Challenge on macOS​

Historically, OneDrive users on Mac experienced a frustrating limitation: while Windows users could freely designate various drives for cloud sync, Mac support for external storage was inconsistent and, for many, practically absent. Earlier in 2024, Microsoft appeared to bridge this gap by announcing support for external drives. However, upon closer inspection, it became evident that the feature was restricted to drives labeled by macOS as “non-removable”—incompatible with standard external SSDs, USBs, and most everyday portable drives.
This left many users, especially creative professionals working with large media files, in a bind. With the cost of high-capacity internal SSDs remaining steep and MacBooks often shipping with modest base storage, the ability to offload OneDrive folders onto external drives was a critical need hovering unfulfilled.
Now, following months of feedback and apparent behind-the-scenes development, Microsoft has removed this barrier. OneDrive for macOS can direct its sync folder straight to nearly any removable drive—so long as it’s formatted as APFS (Apple File System) and meets strict security conditions. This update represents both a technical leap and a reflection of Microsoft’s ongoing investment in supporting enterprise-grade workflows on Apple hardware.

How OneDrive Removable Drive Support Works​

With the new functionality, Mac users can now:

• Select an APFS-formatted removable drive as their OneDrive sync location.
• Experience seamless syncing, with the process automatically pausing if the drive is ejected or disconnected.
• Upon reconnection and relaunching OneDrive, enjoy automatic resumption of file transfers and updates.

This workflow mirrors user experience on Windows but accounts for macOS-specific file system and security nuances. For users managing large or frequently changing libraries—think video editors working off a portable SSD, or researchers with terabytes of datasets—this change can dramatically streamline daily operations.

Key Technical Requirements​

Despite the breakthrough, Microsoft’s new support comes with non-negotiable prerequisites:

• The external drive must be APFS-formatted. Older HFS+ or exFAT-formatted drives are ineligible.
• The drive must be encrypted and protected by FileVault. Plain, unencrypted external volumes won’t work.
• Users must be running macOS 15.0 or later—the upcoming “Sequoia” release at the time of writing. This version introduces APIs vital to reliable external drive sync.
• OneDrive version 25.097 or later is required. Older app builds will not expose the feature.
• Only locally-attached, non-read-only drives are valid destinations. Network drives, read-only, or quarantined volumes are explicitly unsupported.

It’s also important to note a key limitation: moving your external drive between different Macs does not preserve OneDrive’s sync status. Each Mac must be configured from scratch, given OneDrive’s security model and reliance on local credentials for encryption and folder mapping.

Usability: Strengths and Remaining Pain Points​

By listening to user requests and addressing the external drive dilemma, Microsoft has demonstrably improved the everyday experience for Mac-based OneDrive subscribers—particularly those with large storage needs or complex device setups.

Major Strengths​

• Storage Efficiency: Users can now store massive OneDrive folders off the more limited (and more costly) internal SSD, avoiding the need to constantly reconfigure selective sync options.
• Seamless Recovery: When a drive is unplugged, OneDrive halts sync without corrupting files or creating sync conflicts—a potential risk with previous, unofficial workarounds.
• Enterprise Security Integration: By mandating APFS and FileVault, Microsoft ensures that sensitive company or research data remains protected, even if a portable drive is lost or stolen.
• Parity With Windows: The update closes a long-standing gap between Windows and macOS users, supporting greater consistency in cross-platform organizations.

Persistent Limitations​

While the update is broadly positive, several constraints remain:

• APFS and FileVault Requirements: Not all external drives can be easily reformatted to APFS or encrypted with FileVault—especially those used with older Macs or mixed-OS environments. Users must be comfortable erasing and setting up their drive from scratch.
• macOS 15.0 Exclusivity: At launch, only those upgrading to the newest version of macOS (or developers running beta software) will benefit. Many organizations are slow to upgrade, so full impact may be delayed.
• No Plug-and-Go Across Multiple Macs: Unlike some cloud solutions, plugging the same drive into another Mac does not continue sync seamlessly. This restricts utility for users hopping between several workstations.
• Lack of Networked Drive Support: As with prior OneDrive releases, network shares and NAS-based workflows remain unsupported. Power users with more complex storage setups will still need custom scripts or third-party tools.

APFS, FileVault, and Security Impacts​

Microsoft’s insistence on APFS and FileVault for supported drives highlights a clear focus on maintaining a security baseline consistent with enterprise and regulated environments.

What is APFS?​

APFS (Apple File System) is Apple’s modern, high-performance file system designed for SSDs and flash storage. It offers substantial advantages:

• Improved file metadata handling for rapid file copies and snapshots.
• Enhanced reliability and crash resilience.
• Native support for features like space sharing and strong data integrity.

APFS is now standard on all Macs shipping with macOS 10.13 and later. But users upgrading from older systems or using previously formatted exFAT or HFS+ drives will need to reformat (erasing all contents) to comply with OneDrive’s new demands.

FileVault Protection​

FileVault, Apple’s full-disk encryption tool, protects data on internal and external drives with robust XTS-AES-128 encryption. For businesses and users dealing with confidential information, this requirement may be critical—ensuring that sensitive files aren’t left vulnerable on misplaced or stolen drives.
Mandating FileVault also eliminates a primary risk of syncing corporate data to removable media: the chance of breach if a physical drive goes missing.

Real-World Scenarios: Who Benefits the Most?​

This change is not just a technical curiosity; it promises substantive workflow improvements across multiple user groups.

Creative Professionals​

Photographers, videographers, and music producers commonly work from high-speed external SSDs, frequently swapping media between locations and devices. Previous OneDrive restrictions forced them either to sync only a partial library or to clog their MacBook’s internal drive with files. The update delivers new flexibility, letting large media repositories live entirely on fast, encrypted external drives.

Corporate Power Users​

Consultants, field engineers, and researchers often carry extensive documentation or datasets across multiple client sites or labs. By linking OneDrive directly to a secured external drive, they can guarantee up-to-date access to essential project materials while keeping sensitive data encrypted at rest.

Education and Research​

Academics and students shuttling between classrooms, labs, and personal devices can now maintain a fully mirrored set of notes, papers, and datasets without breaching institutional security policies—or exhausting their institution-supplied device’s local capacity.

Setup: Getting Started With OneDrive on APFS Removable Drives​

For those eager to leverage the new feature, setting up can be straightforward—but it does require careful adherence to requirements.

Step-by-Step Guide​

• Update macOS
  Confirm your Mac is running at least macOS 15.0 (Sequoia). If not, join Apple’s beta program (if available) or await general rollout.
• Format Your Drive to APFS
• Open Disk Utility, select your removable drive, and choose “Erase.”
• Set the format to “APFS.”
• Warning: This erases all data on the drive.
• Enable FileVault Encryption
• Within Disk Utility or via System Settings > Privacy & Security > FileVault, turn on encryption for the external drive.
• Set a strong password and store the recovery key securely.
• Install Latest OneDrive
• Download or update to OneDrive version 25.097 or newer via the Mac App Store or Microsoft’s website.
• Configure Sync Location
• During OneDrive setup (or via preferences), specify the external drive as your sync folder.
• Allow Indexing and Permissions
• Grant OneDrive full disk access and respond to any system prompts for permissions or indexing.
• Start Syncing!
• Begin syncing files as normal. If you disconnect the drive, expect a OneDrive error warning until the drive is reconnected.

Troubleshooting Tips​

• Permissions Errors: Double check both APFS format and that FileVault shows as activated for the drive.
• Drive Not Appearing: Only non-network, non-read-only APFS drives (with FileVault) will appear as selectable.
• Unexpected Stops: Force-quit and relaunch OneDrive after reconnecting the drive if sync does not resume automatically.

Broader Implications for Microsoft’s Cloud Strategy​

Microsoft’s ongoing push for platform parity between Windows and macOS is evident here—and the stakes are high. Cloud storage is now the backbone of hybrid work and collaboration. By narrowing one of the last remaining experience gaps for Mac users, Microsoft strengthens OneDrive’s appeal in competitive enterprise and education sectors.
But the approach is characteristically “secure by default”—reflecting lessons learned from previous headline-grabbing breaches involving improperly secured portable media. Requiring both a modern file system and disk encryption may inconvenience casual users but aligns squarely with enterprise IT expectations.
It’s also notable that Microsoft rolled this feature out first to OneDrive Insiders, a strategy that allows for controlled feedback and vetting before broad public availability—a prudent step, given the risks of sync corruption or data loss with portable drives.

Critical Analysis: Balancing Progress With Caution​

While the arrival of removable drive support for OneDrive on Mac is widely celebrated, there are potential pitfalls.

Strengths​

• Enhanced Security: Combining APFS and FileVault offers a strong defense against physical theft or unauthorized access.
• Real World Usability: The feature reflects how Mac users work today—especially in data-heavy, mobile, or multi-device environments.
• Alignment With Platform Norms: Microsoft’s approach follows Apple’s own security and filesystem modernization, building atop native tools and APIs.

Risks and Cautions​

• User Hassle for Reformatting: Those with existing datasets on HFS+ or exFAT drives face the pain of erasing and redeploying content, with all the inherent risks of data migration.
• Potential Sync Inconsistencies: While robust, external drive sync is inherently more prone to disruption due to physical disconnection, power-saving unmounts, or drive health issues. Users should develop good backup hygiene and never entrust sole copies of irreplaceable files to a single drive.
• Unverified Claims: As of publishing, this feature’s roll-out is still limited to OneDrive Insiders. Wider availability dates, and full performance/compatibility with every APFS drive, cannot yet be independently verified. Users should consult Microsoft’s official documentation and the OneDrive Insider release notes before committing production data.
• Anticipated Software Bugs: Early testers have occasionally reported that OneDrive does not always resume sync perfectly after unexpected drive removals—a risk for anyone relying on always-up-to-date files. As deployments scale, further bug fixes and improvements should be expected.

Alternatives: What If OneDrive Doesn’t Meet Your Needs?​

For those unable or unwilling to reformat or encrypt external drives, alternatives include:

• Dropbox: Offers more liberal support for external drives, though with its own limitations.
• Google Drive for desktop: Allows folder sync to external drives, but lacks the deep file system and security integration OneDrive enforces.
• Synology Drive / Nextcloud: For users with network-attached storage, these self-hosted solutions offer network sync not currently supported by OneDrive.

Still, for the millions of business and enterprise users in Microsoft-powered environments, OneDrive’s update marks a major leap forward in closing the Mac vs Windows feature gap.

Conclusion: A Meaningful Step For Mac Users​

By rolling out APFS-formatted removable drive support, Microsoft affirms its deepening commitment to parity between macOS and Windows. This change instantly makes life easier for power users saddled with large OneDrive folders and complex workflows. The new feature brings enhanced flexibility, upholds enterprise security standards, and signals a keen awareness of how modern professionals actually get work done on Macs.
However, the upgrade comes with caveats. Users must be prepared to reformat drives, embrace Apple’s FileVault encryption, and keep their systems on the bleeding edge of macOS versions. Broader effects will only become clear as the feature moves from Insider builds to stable releases, and as more users stress-test it with real-world, large-scale data.
Ultimately, for Mac-based OneDrive devotees, this is a step in the right direction. Anyone frequently balancing files between internal storage and external drives should closely track Microsoft’s rollout, consider updating to macOS 15.0, and weigh whether the benefits outweigh the setup hurdles and transitional pains. For many, this long-awaited sync flexibility will be worth every step.

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Source: Windows Report OneDrive for Mac now supports syncing to APFS-formatted removable drives