The macOS File Sync Loop Affecting Multi-Step Automations — And the Folder Action Throttle Fix Users Found

macOS users have long relied on automation workflows to streamline file management tasks, especially in professional settings where repetitive tasks can eat up significant time. However, a new challenge has emerged in recent macOS builds that directly impacts the reliability of multi-step automations: a file sync loop triggered by real-time cloud storage services. This glitch, in turn, can throttle folder actions and render automated processes unstable or incomplete.

TL;DR: A macOS issue involving file syncing and cloud storage interferes with multi-step file automations like Folder Actions and Hazel scripts. The root cause is a sync loop where modified files are repeatedly written and resynchronized, confusing automation triggers. Users have discovered a workaround by throttling or delaying Folder Action responses to reduce false triggers. Although it’s not a perfect fix, it significantly restores stability to broken automations.

Understanding the File Sync Loop Problem

At its core, the file sync loop issue appears to stem from how macOS interacts with cloud syncing services like iCloud Drive, Dropbox, and OneDrive. When a file is created or modified in a synced folder, the cloud agent quickly attempts to upload the changes. Once synced, the file metadata may update again, causing macOS to interpret it as a “new change”—even if the content hasn’t changed. This sets off a feedback loop of unintended file activity.

For users running automations based on folder events—such as Folder Actions, Hazel rules, or AppleScripts—this translates into scripts being triggered multiple times unexpectedly. What was supposed to be a one-time automation sequence now becomes chaotic, as duplicates, partial processing, or out-of-order automation steps begin to occur.

Professional workflows are particularly affected, including:

• Media teams automating video file conversions post-download
• Design departments auto-exporting images into multiple formats
• Backup routines dependent on clean triggers from a watched folder

Symptoms and Indicators

Although hard to detect at first, users have reported several common signs that indicate their automations are caught in a sync loop:

• Scripts triggering twice or more despite an unchanged source file
• Log files showing multiple instances of the same file being processed
• “File currently in use” errors as simultaneous processes interfere
• Empty or duplicated outputs from batch operations

The most troubling aspect? macOS doesn’t provide any direct error logs identifying the cloud sync service as the culprit. Users are left guessing, often turning off entire workflows in search of a solution.

The Folder Action Throttle Fix

In response, power users and developers have devised a DIY fix: throttling Folder Action triggers by introducing a delay buffer or ignoring recently processed files for a short window of time. While not officially endorsed by Apple, the fix has been remarkably successful among those implementing it manually or through third-party tools.

This approach works by modifying Folder Action or Hazel scripts to:

1. Check the file’s last modification timestamp
2. Evaluate whether a specific threshold (e.g., 10 seconds) has passed since the last known trigger
3. Log processed file names and time to prevent reprocessing within that threshold

As a result, even if the sync loop modifies file metadata, the automation skips any triggers that fall within the throttle window, effectively negating phantom activations spurred by cloud syncing.

Sample Script Strategy

Let’s look at an AppleScript that implements throttling logic for Folder Actions:

on adding folder items to this_folder after receiving added_items
    set now to (current date)
    repeat with anItem in added_items
        set modDate to (get modification date of (anItem as alias))
        if (now - modDate) > 10 then
            -- Proceed with automation
            say "Processing file"
        else
            say "Skipping duplicate trigger"
        end if
    end repeat
end adding folder items to

In this simple logic, files added or modified less than 10 seconds ago are ignored. This short pause is often enough to allow the cloud sync process to settle without spawning secondary unwanted triggers.

Best Practices: Scripting Around Sync Loops

In addition to the throttle fix, users are advised to adopt a combination of good practices to reduce their risk of triggering the file sync loop:

• Use temporary folders outside of sync areas: Process files in non-cloud folders first, then move them into synced directories only upon completion.
• Batch process using interval-based scripts: Instead of Folder Actions, run periodic checks every minute or so via launch agents or cron jobs.
• Disable real-time sync temporarily during intense automation windows, especially batch conversions or importing large media libraries.

Third-Party Tools Coping with the Issue

Popular automation utilities like Hazel have begun including buffer options for new files or re-worked their trigger logic to bypass the problem. Hazel users can now prevent rules from acting on files that have been modified too recently, effectively mimicking the Folder Action throttle behavior.

Meanwhile, developers using Shortcuts or AppleScript are increasingly building their own caching or debounce routines to handle delayed file ingestion more gracefully. This shows a rising trend of adapting automation scripts with real-world error tolerance, a necessity in environments now flooded with background sync processes.

What Apple (Hasn’t) Done Yet

As of macOS Ventura and early Sonoma releases, Apple has not acknowledged the file sync loop as an official issue. Although bug reports have been submitted, there is no system-level throttling or filtering of redundant triggers (at least not publicly). This has prompted the community to take matters into their own hands, sharing script templates and workflow modifications on tech forums and GitHub.

Some users have speculated that internal enhancements to iCloud Drive may be responsible, possibly due to fine-grained syncing intended to preserve data integrity. Whatever the cause, the need for adjustable automation flexibility has never been more apparent within the Apple ecosystem.

Conclusion

The macOS file sync loop is a subtle but disruptive problem that affects automated workflows in profound ways. While not yet addressed by Apple, power users have identified a key workaround—delaying script execution using a throttle buffer. Combined with best practices like non-synced staging folders and smarter job scheduling, this strategy has salvaged many faulty automations from the brink of obsolescence.

Until Apple introduces a reliable native fix, the community fix stands as a testament to the adaptability of users and the resilience of macOS automation culture.

FAQ

• Q: What causes the file sync loop in macOS automations?
  A: The loop is triggered by cloud services like iCloud Drive repeatedly modifying file metadata, which macOS interprets as new file changes, triggering automations multiple times.
• Q: Which automation tools are affected?
  A: Tools using folder-watching triggers such as Folder Actions, Hazel, AppleScript, and Shortcuts are particularly susceptible.
• Q: How can I fix the repeated file triggering issue?
  A: Insert a time-based throttle in your script to ignore files altered within a recent time window (e.g., last 10 seconds), filtering out false triggers.
• Q: Does this issue affect all macOS versions?
  A: While more noticeable in recent versions like Ventura and Sonoma, earlier versions may also be affected when using updated cloud sync apps.
• Q: Is there a tool that automates this fix?
  A: Third-party apps like Hazel have built-in options that mimic this fix. Others rely on custom AppleScripts or shell scripts for implementation.