Can't get MacOS to install applications to APFS formatted SSD

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Level 1

9 points

Can't get MacOS to install applications to APFS formatted SSD

Hey y'all I'm at my wits end but I thought I'd try asking here before msging support. I got a mac mini and it was my first mac in literal years. And by years I mean that I didn't even know formatting an SSD a certain way was a thing. So ofc, when I first set it up, I just chose whatever thinking it didn't matter. Whatever being - a different partition map than "guid", and Mac Journaled.

I dragged and dropped the Wuthering Waves game onto the ssd and it worked perfectly. But later I realized that I couldn't choose the SSD as an installation drive because, according to Apple, the drive had to be formatted to APFS with a guid partition. Unfortunately that meant erasing everything on the drive but whatever, I did it.

Now, the appstore recognizes the SSD as something it can install applications too, BUT, no matter what I try, it won't install the WuWa anymore. It downloads the whole thing and then just gives me the typical, "this app cannot be installed" error. I already made sure everything is up to date as well but it still won't install. Any suggestions before I resort to contacting support?

Posted on Jul 10, 2025 01:54 AM

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Answer 1

Old Toad

Level 10

214,296 points

Jul 13, 2025 11:26 AM in response to VisceralMel

Most apps expect them to be in the Applications folder on the same volume as the system. I assure you don't have enough space to have everything on your boot drive. Therefore here's what I'd do:

1 - copy the Pictures, Movie and Documents folders to the external SSD.

2 - verify the Photos and Music libraries work as intended on the external drive and files in the Documents folder are good, open and close some of them, before deleting the contents of those folder on the boot drive.

3 - remove the existing Documents, Photos and Music folders from the Finder's side bar and add the folders from the external SSD by dragging them into a Finder window sidebar. You can also add them to the Dock if desired.

4 - make sure you have a Time Machine drive to backup both your external SSD and your boot drive. Or some other backup system like Carbon Copy Cloner.

The goal is to keep a minimum of about 80-100 GB free on the boot drive and external SSD to facilitate optimal system and application performance.

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Answer 2

tbirdvet

Level 6

16,703 points

Jul 13, 2025 03:24 PM in response to VisceralMel

This could be app related. As noted before even when you install an app on the external some of the app OS files may need to be installed on the internal drive to operate correctly. Therefore you may find some apps have no issues installing directly to the external but others do.

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Answer 3

tbirdvet

Level 6

16,703 points

Jul 10, 2025 10:58 AM in response to VisceralMel

Please clarify. Are you trying to install the app on an external drive or your internal drive? What model of Mac and what drive size do you have? This app looks large and requires space on the internal even though you may want to run from the external.

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Answer 4

Jul 13, 2025 12:13 AM in response to VisceralMel

The normal procedure is to install apps on the boot drive which I am guessing is your internal . . . unless you are booting from the external?

Explain clearly which one is your boot drive and exactly what apps are you trying to install.

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Answer 5

VisceralMel Author

Level 1

9 points

Jul 13, 2025 06:49 AM in response to Ian R. Brown

By "normal procedure" are you implying that any apps I download have to be installed on the boot drive first and then I have to transfer them to the external SSD? Rather than just installing an app directly onto said external SSD? (Because I think I read a comment like this somewhere...)

And yes I am def booting from the Mac mini itself. Considering that I only just started to re-familiarize myself with all things Mac, booting from an external drive sounds like something I don't want to toy around with right now.

If you refer to my initial post, I'm only asking this because I read that with the Sequoia 15.1 update, we'd be able to install apps, from the appstore, directly to an external drive. I did everything you're supposed too and my appstore does give me the option to download and install directly to my external drive. But after the app is finished downloading, it tells me that it can't be installed.

Hence I was wondering if anyone else encountered this problem before or if I'd have to message support.

The app I was trying to download is a game called Wuthering Waves and it's around 60gb.

I did download a video editing app and that one downloaded and installed just fine to the external drive - which only added to my confusion.

Anyway, now you have me wondering if my stuff is glitched cuz I had already downloaded the game before, OR, if some apps do have to be installed to the boot drive first and then transferred because - I freed up enough space to download the game to the boot drive and then I just transferred it to the external and it's working fine. BUT, I totally didn't want to offload and delete things just to be able to do that so if anyone knows anything about this, pls feel free to add your two cents.

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Answer 6

VisceralMel Author

Level 1

9 points

Jul 14, 2025 02:39 AM in response to tbirdvet

Thanks dude. I had no idea before this but after this experience I'm guessing that's exactly what happened here and I'm gonna do what Old Toad said. Plus that way if I ever encounter a problem like this again I'll have enough space to download to the boot drive and then just transfer it as I've been doing. Thanks again y'all!

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Answer 7

VisceralMel Author

Level 1

9 points

Jul 12, 2025 10:40 PM in response to tbirdvet

This is an external SSD which is why I say I was able to "drag and drop" the application before. And I'm on a standard Mac mini with the m4 chip.

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Answer 8

VisceralMel Author

Level 1

9 points

Jul 14, 2025 02:35 AM in response to Old Toad

Thanks! This is super helpful!

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