Pebblett Author

Level 1

13 points

Transferring large files from iMac SSD to mirrored LaCie drives

Hi, 2020 27" iMac, 1TB SSD. Have 5TB LaCie, mirrored. Bought a 2nd 5TB Lacie, thinking I can put say large files on both LaCies and take them off the SSD as it's only 1TB. I don't know how to do it, or if it's possible. I didn't know to query this beforehand as I thought it was something these days that can be done!

Basically, my SSD is full, I want to only keep 'the essentials' on it, and copy the rest to the LaCie/s. Glad to hear any suggestions.

[Edited by Moderator]

Original Title: LaCie, Mirror & iMac

iMac 27″

Posted on Oct 8, 2025 10:16 AM

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Top-ranking reply

Level 10

90,376 points

Posted on Oct 8, 2025 11:40 AM

You can create new folders on an external drive, then move your documents and other files to them.

If you are looking to free up space, you can also move your Photos, Music, Movie Libraries to an external hard drive.

Move your Photos library to save space on your Mac - Apple Support

Change where your music files are stored on Mac - Apple Support

Move your iMovie for Mac library - Apple Support

In addition to the previous links, see > Free up storage space on Mac - Apple Support

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3 replies

Top-ranking reply

Level 10

90,376 points

Oct 8, 2025 11:40 AM in response to Pebblett

You can create new folders on an external drive, then move your documents and other files to them.

If you are looking to free up space, you can also move your Photos, Music, Movie Libraries to an external hard drive.

Move your Photos library to save space on your Mac - Apple Support

Change where your music files are stored on Mac - Apple Support

Move your iMovie for Mac library - Apple Support

In addition to the previous links, see > Free up storage space on Mac - Apple Support

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Level 10

215,082 points

Oct 9, 2025 10:31 AM in response to Pebblett

Be warned that if you copy your Photos library to the external drive it must be formatted APFS (SSD) or OS X Extended (Journaled) of an HDD.

Otherwise the library will be damage and you'll lose data.

Also you should backup the external drive with Time Machine just as you would the boot drive.

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Level 10

223,872 points

Oct 8, 2025 10:52 AM in response to Pebblett

Have you identified the data you want to offload to external storage?

We can't do that for you.

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Transferring large files from iMac SSD to mirrored LaCie drives

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