Error 'Couldn't communicate with a helper application' after Migration Assistant on new MacBook Pro

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Error 'Couldn't communicate with a helper application' after Migration Assistant on new MacBook Pro

Hi all. I recently purchased a new MacBook (MacBook Pro, 14-inch, 2024) and transferred my data over via Migration Assistant from my old Mac (MacBook Pro, 13.5-inch, 2019).

About 60% of my files transferred over no problem. However, some of them are not opening with the error "Couldn't communicate with the helper application". I know this isn't a Preview problem because when I attempted to open these in other applications e.g. Photoshop, they still do not open and instead I got this error "Could not complete the command because of a disk error" via Photoshop itself.

Some additional context that may be useful: My old Mac was running low on space, but it was out of space. My iCloud storage is out of space, so I am unsure if this is linked to a cloud issue - although "disk error" makes me think that it may not be iCloud related. As mentioned, some files transferred over just fine. There seems to be no issue in terms of it being date-dependent (some old files open, some old files don't open, etc) / no specific file type that does not open.

I do still have my old Mac and can transfer these files over manually, although there's quite a few of them in a random configuration so it would take a lot of time, which is why I am trying to find an alternative solution. In a similar post I saw something about permission, however I have permission checked to "read & write".

Interested to hear any advice you all may have. Thank you!

[Re-Titled by Moderator]

Original Title: Following migration assistant some files will not open with error "Couldn’t communicate with a helper application."

MacBook Pro 14″, macOS 15.5

Posted on Aug 1, 2025 8:19 PM

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Answer 1

Top-ranking reply

Grant Bennet-Alder

Level 10

141,235 points

Aug 2, 2025 7:45 AM in response to lucy_f

<< I got this error "Could not complete the command because of a disk error" via Photoshop itself. >>

That is very concerning. It is possible that there is some directory damage on the drive, possibly imported with your old data.

A quick fix may be to boot into Safe mode, which does a simple pass of RepairDisk/FirstAid on the Mac Volume as it starts up.

if no relief (or it stall there) you may need to boot into Recovery for a deeper repair.

Launch Disk Utility.

Make certain the tiny View menu is set to "show all devices"

Select each and click RepairDisk/FirstAid:

the Physical device,

the container-disk,

and each Volume in turn.

if any throw errors, run the repair again.

if any do not come clear, you may need to re-image the device. On a modern Mac do NOT just erase the Physical Device to do this, use the "Erase all content an settings" as described here:

Erase your Mac and reset it to factory settings - Apple Support

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Answer 2

SravanKrA

Level 10

432,018 points

Aug 2, 2025 2:27 AM in response to lucy_f

If you’re transferring between two Macs: Transfer to a new Mac with Migration Assistant - Apple Support (IN)

Restart both machines.
Make sure both are on the same macOS version (ideally).
Open Migration Assistant again on both and retry.

If that fails...

Run Migration Assistant from Applications Folder (not Spotlight)

Sometimes Spotlight/Launchpad may launch it without full permissions.

Go to Applications > Utilities > Migration Assistant.
Right-click > Open.

This forces macOS to bypass certain security checks and may fix the issue.

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