Odd Mac hard drive configuration

[andygo]

I have recently purchased a new 27 inch imac with a fusion drive on the basis I had a 1tb t5 ssd drive to use as an external drive for apps etc. All is working well but:

My 1 tb fudsion drive has somehow partitioned itself into 2 partitions: 1 x Macintosh HD and 1 x Macintosh HD -Data.

in Disk Utility they both report as a 1.03TB drive with similar used values, similar other volumes values and similar free space values at around 350gb each.

If i explore in the finder app, both have similar ( but dated differently in several cases) folders and content.

Whats going on?

[Bikerjon]

What version of Mac OS?

[mattley]

Here's how to prep a fusion drive https://support.apple.com/en-gb/HT207584

[The Moose]

Time machine/other backup partition?

[andygo]

Time machine is on another external HD.

Had my previous mac 6 years. It was also running Mojave and the 1tb HDD was as you would expect on that one.

[Bikerjon]

HD-Data is an additional APFS volume that the next Mac OS version (Catalina) creates. So if that machine was used to try the Catalina beta then that would explain how it got there.

If it's a secondhand machine I'd be inclined to fully erase the internal drive and reinstall Mojave

[andygo]

Aahh, that explains it. I did put Catalina on, but restored it back as it wouldn't work with Firefox.

Think I might be able to educate the Apple tech hotline that I'm currently on the phone to!

Top work, lol .

Just got off the phone from Apple tech support, they have sent me instructions on how to rejoin the fusion drive and restore the computer. Not sure that is the issue though. I'll prolly just leave it as is at the mo and delete the duplicated data until Catalina launches as the final version.

Edited by andygo on Friday 16th August 09:09