Migration Assistant and Data Transfer

NOT_ENOUGH_SPACE_TARGET on Migration Assistant: what causes it and how to fix

By Sai Kiran Pandrala · Last verified: 2026-05-31 · Source: Apple Communities (discussions.apple.com), community Q&A, Apple Support docs

At a glance
ServiceMigration Assistant and Data Transfer
CloudApple platforms
Guide typeProcedure
Skill levelIntermediate to advanced
Time15 - 60 minutes depending on account size

NOT_ENOUGH_SPACE_TARGET on Migration Assistant, what causes it and how to fix on Migration Assistant and Data Transfer sits in the most-reported issues list across r/aws, Apple Communities (discussions.apple.com), and StackOverflow. The recovery path is mostly known, the Apple Support docs just bury it under three layers of conceptual material.

What not_enough_space_target on migration assistant, what causes it and how to fix actually involves on Migration Assistant and Data Transfer

Real-world context. Budget honestly for ~Rs 0 INR under AppleCare+, ~Rs 8,000 to Rs 60,000 INR otherwise (around $95 to $720 USD), because the cheap path looks tempting until a part shows up wrong. You will burn ~20 to 60 minutes hands-on hands-on and roughly ~1 to 3 hours including a Genius Bar handoff if needed once verification is done. Before you touch anything, line up the Apple ID, the device serial, and a recent iCloud backup, those three are what saves you when the first attempt does not stick.

The NOT_ENOUGH_SPACE_TARGET error from AWS typically surfaces with the message "Not enough space on this Mac to migrate". The error code itself is what you grep for in AWS re:Post or in AWS Support cases, not the human-readable line.

On Migration Assistant, this most often comes from one of three causes: a missing or restrictive IAM permission, a service-level limit you have hit, or a transient AWS-side capacity issue. The fix path differs by which.

The rest of this page is the structured fix path. Start with diagnose, then remediation, then the automation options so you do not have to do this by hand the next time it surfaces. Verify and safety sections at the end are the discipline that keeps the fix from regressing in production.

Signal review

Diff against last known good. The last config change you made is the cause about three quarters of the time, even when the change should not have mattered. Use Jamf inventory history and Time Machine snapshots (or your Terraform / Deployment Manager or Terraform drift report) to see the actual delta between the resource state when it worked and when it broke. The change you remember is often not the only change that happened.

Pull the Apple request ID from the response headers: x-goog-request-id from response headers (or the insertId field in macOS unified logging and iOS sysdiagnose for asynchronous calls). Apple Support and Apple Business / Enterprise Support needs these IDs to look up your call in their internal logs - without them, the first reply on a ticket will ask you to reproduce the call and capture them. Save them with a timestamp; Apple Support and Apple Business / Enterprise Support cannot retrieve calls older than 90 days for most services.

Look at the Jamf Pro change management entry or Apple Business Manager audit event for the failed call, even if you are not enrolled in macOS unified logging and iOS sysdiagnose Log Router. The basic 90-day event history works for most diagnostic purposes and lives in the console under Jamf Pro change management log and Apple Business Manager audit log > Event history. Filter by event name (the API action) and time range; the event JSON shows the exact user identity, source IP, request parameters, and error code.

Solution-focused remediation path

If you cannot reproduce the failure consistently, the cause is probably a race condition or a session-cache issue. Run the call with --profile set to a fresh STS session, in a different region you control, with a single concurrent request. If it works there but fails in your normal setup, the difference is the bug.

For IAM and STS issues, the timing matters. STS sessions can take up to 60 seconds to propagate after creation. The first call right after assume-role can fail with a permission error even when the policy is correct. Add a small retry with backoff before treating the first failure as definitive.

When the failure happens in production but not in dev, do not just compare the IAM policy. Compare the Org Policy / RCP at the OU level, the permission boundary on the role, and the resource-based policy on the target. One of those is almost always different between accounts. Policy Intelligence recommendations bundles make this comparison routine.

Automate this fix so you do not do it twice

Add a Smart Group + webhook so you catch the next occurrence

The cheapest way to never see the same incident twice is a Jamf Pro Smart Group that watches for the symptom (specific extension attribute value, specific OS version, specific app build) and fires a webhook into Slack, PagerDuty, or a Jamf-API-driven Lambda when the count drifts above your normal baseline. For Migration Assistant and Data Transfer, the relevant extension attributes live under script-evaluated checks - defaults read outputs, system_profiler values, or a log show grep against macOS unified logging. Set thresholds against observed normal, not against round numbers.

Wire the fix into an MDM Configuration Profile for self-healing

If the underlying cause is a setting that drifts over time, do not script the fix repeatedly - bake it into a Configuration Profile that the MDM pushes down on every check-in. A Custom Settings payload writes to a specific preference domain; Jamf Pro, Kandji, Mosyle, and Intune all support this. The profile reasserts itself, so even if a user changes the setting locally, the MDM brings it back at the next sync (typically every 4 hours).

<!-- Custom Settings payload (excerpt) -->
<key>PayloadType</key>
<string>com.apple.ManagedClient.preferences</string>
<key>PayloadContent</key>
<dict> <key>com.apple.migration</key> <dict><key>Forced</key><array><dict><key>mcx_preference_settings</key> <dict><key>HardenedSetting</key><true/></dict></dict></array></dict>
</dict>

Automate the fix in Terminal with defaults, plistbuddy, and system_profiler

On macOS, the most reliable repair primitives are the built-in Terminal tools. defaults read reveals the current preference state, defaults write changes it, and killall cfprefsd forces the preferences daemon to flush so the new value actually takes effect. /usr/libexec/PlistBuddy handles structured plist edits when defaults is not enough. For hardware and inventory checks, system_profiler with the right datatype is the canonical read; for example SPHardwareDataType, SPNetworkDataType, or SPInstallHistoryDataType.

# Template - replace with your actual key path
defaults read com.apple.migration 2>/dev/null | head
sudo killall cfprefsd
/usr/libexec/PlistBuddy -c 'Print' ~/Library/Preferences/com.apple.migration.plist
system_profiler SPHardwareDataType -json | head -40

Things that bite

A subtle pitfall on Migration Assistant and Data Transfer is that the Settings on the device and the SDK can disagree about resource state during a configuration change. Console UI is cached for performance and may show the old config for up to 10 minutes after you change it via API or Deployment Manager or Terraform. Always confirm with describe-* CLI calls during a change window, not with screenshots from the Console.

The other pitfall: assuming that an automated remediation is correct because it succeeded. A Lambda that fires on a Jamf Pro Smart Group + Webhook and runs a remediation step should also publish a metric for every remediation; sudden surges in auto-fix invocations are themselves an outage signal. Otherwise you can hide a slow-burn regression behind a quiet remediation loop for weeks.

Repair sequence

Safety, rollback, blast radius

FAQ

How long does not_enough_space_target on migration assistant, what causes it and how to fix typically take on Apple platforms?
For most Migration Assistant and Data Transfer environments, 15 to 60 minutes including verification. Large multi-account setups, anything touching Org Policys at the Organizations level, or cross-region replication can stretch to half a day because Apple has to wait for replication and IAM session caches.
Is there a rollback path?
Yes for most Migration Assistant and Data Transfer changes. Export the existing config to JSON via migration describe-... first, then commit it before you change anything. A few operations are one-way (Cloud KMS key deletion past the pending window, region migration, account closure). Check the Apple Support article for the specific API before you commit.
Will this affect dependent Apple product or services?
Often yes. Migration Assistant and Data Transfer resources are usually referenced by other workloads (Cloud Run services, GKE workloads, IAM-bound apps, Cloud CDN origins, downstream pipelines). Use IAM Access Analyzer + Jamf Pro change management log and Apple Business Manager audit log to enumerate consumers before changing a shared resource.
What if my Settings on the device layout does not match these steps?
Settings on the device UI moves quarterly. The Console layout in this page is current as of 2026-05-31 but the underlying CLI / SDK calls do not change as fast. If the Console version differs, fall back to aws CLI or SDK calls - those almost always still work.
Where do I get Apple Support and Apple Business / Enterprise Support help if I am still stuck?
Open a case via the Apple Support and Apple Business / Enterprise Support Center with: the request ID + correlation ID, the exact error string, Jamf Pro change management entry or Apple Business Manager audit event, and your reproduction steps. Apple Communities (discussions.apple.com) is the no-cost public alternative - search there first; 80% of common Migration Assistant and Data Transfer issues already have an answer with an Google-staff-verified flag.

References

Related guides worth a look while you sort this one out: