iMac Pro - Sequoia. Finder stuck on 'estimating time' dialogue on copy

I am trying to copy a 400GB file from a 2TB external SSD to a 4TB external SSD. both are connected directly to the USB3 ports on the rear of my iMac Pro.

I have also tried copying to my NAS.

I am running the latest version of Sequoia

In all cases, the Finder copy dialogue sticks on "estimating time remaining" and will stay in that state overnight.

Can anybody suggest a solution?

Thanks

iMac (2017 – 2020)

Posted on Jan 1, 2026 2:35 PM

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Question marked as Top-ranking reply

Posted on Jan 1, 2026 6:19 PM

Are these external drives formatted for the Mac? Not PC drives?

The latest version of Sequoia is 15.7.3.


You might give a try to running Disk Utility First Aid against both of those external drives. There may be some directory or file corruption that needs to be addressed.

Repair a storage device in Disk Utility on Mac - Apple Support


You might also try booting in safe mode and then giving your file copy another try while running in that mode.

Safe mode will often correct weird software behavior by forcing the OS to clear caches, do disk repair and other self-maintenance and housekeeping and temporarily disables third-party mods.

How to use safe mode on your Mac - Apple Support 


6 replies
Question marked as Top-ranking reply

Jan 1, 2026 6:19 PM in response to tontoe

Are these external drives formatted for the Mac? Not PC drives?

The latest version of Sequoia is 15.7.3.


You might give a try to running Disk Utility First Aid against both of those external drives. There may be some directory or file corruption that needs to be addressed.

Repair a storage device in Disk Utility on Mac - Apple Support


You might also try booting in safe mode and then giving your file copy another try while running in that mode.

Safe mode will often correct weird software behavior by forcing the OS to clear caches, do disk repair and other self-maintenance and housekeeping and temporarily disables third-party mods.

How to use safe mode on your Mac - Apple Support 


Jan 1, 2026 6:21 PM in response to tontoe

So just to confirm.....you are trying to transfer a single file that is 400GB in size?


What are the exact make & models of these two USB drives? Provide a link to their product page if you can.


What file systems are each of these two drives?


Are these drives connected to the USB-A or USB-C ports? Since you mentioned USB3 ports.....I assume you mean the traditional USB-A ports?


Have you tried booting into Safe Mode in order to attempt to transfer the file?


You should also try running Disk Utility First Aid on both external drives. Even if the First Aid summary says everything is "Ok", click "Show Details" and scroll through the report to see if there are any unfixed errors or warnings. If so, then run First Aid again until they are gone, but after several scans the errors remain, then they cannot be repaired by First Aid. If either one is using the APFS file system, then run First Aid on the hidden Container which can be revealed by clicking "View" within Disk Utility & selecting "Show All Devices".

Jan 2, 2026 6:46 AM in response to HWTech

Thank you 🙏 @HWTech


The SSDs are [I think] Sandisk 1TB and 4TB, in UGreen SSD enclosures. I will check the exact make/model numbers.


I formatted them via Disk Utility on my MacBook Air M2 running Sequoia. As far as I remember, it was APFS, but I will check.


I'll also try Safe Mode and running First Aid on both of them.


They are connected directly to the ports on the back of the iMac Pro - one to a USB-A port and one to a USB-C/Thunderbolt port.


Thanks again for your advice. I will follow your suggestions, verify the information, and report back.

iMac Pro - Sequoia. Finder stuck on 'estimating time' dialogue on copy

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