Cannot install Mojave because of lack of space

Question

Cannot install Mojave because of lack of space

I have a late 2013 iMac with a 1TB HDD. We use a A 256gb USB SSD drive as the boot drive. However when we try to install Mojave it gives a space error. It says "the target disk is too small for this operation. Quit the installer to restart your computer and try again"

However the SSD drive has 155GB free

Yet ... if look in storage in About this mac it says the SSD drive is full (right image), yet if I "get info" from the Finder it says there is 155GB free (see left image)

The only item which is 150GB on my computer is the photos library but if I look in photos / preferences it says the library is located in the iMac HDD

And when I look at the size of each folder in the SSD it shows there is only about 100GB used and therefore 150GB free.

So ... my guess is there is 155GB free on the SSD but for some reason some parts of the system think it is full with photos so when I try to update the OS it gives the error.

The problem started with the last OS update before that it was fine and we currently run 10.13.5

How can I solve this issue? Thanks

Posted on Sep 28, 2018 2:17 PM

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Answer 1

macjack

Level 10

111,242 points

Sep 28, 2018 2:29 PM in response to richardmclarke

The Storage tab is known to report incorrectly.Also check by choosing your Mac HD and "Get Info" (command-i). It may be different. Try rebuilding Spotlight index.

If that doesn't work download Omni DiskSweeper:

https://www.omnigroup.com/more

DiskSweeper can give you a more accurate read of disk space than Finder or Storage Tab of About this Mac. Itcan also show you the precise size and location of all your files. It will inventory your disk starting from the files that take up the most space. If you want you can even delete files from OmniDisk Sweeper. But be careful some of the items may be important to your system.

Also, just running ODS should fix the storage number.

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Answer 2

dialabrain

Level 10

136,127 points

Sep 29, 2018 6:50 AM in response to richardmclarke

Try re-indexing Spotlight then restart.

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Answer 3

Old Toad

Level 10

215,760 points

Sep 29, 2018 11:33 AM in response to richardmclarke

Try booting into Safe Mode, <a href="https://support.apple.com/en-us/HT201262">Mac OS X: Starting up in Safe Mode</a>, and installing from there.

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Answer 4

Nov 4, 2018 5:00 PM in response to richardmclarke

I had this issue too and I fixed installing the Mojave OSX from a booteable USB and format the HDD with the APFS selection, I make a new and clean installation and I don't know if with an upgrade the problem was the same, in my case selecting the format that i mentioned the problem not appear any more.

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Answer 5

dialabrain

Level 10

136,127 points

Sep 29, 2018 8:33 AM in response to richardmclarke

You're welcome. The only thing I can think of is the installer doesn't like the fact you are booted from an external drive but that's pure speculation on my part. I guess you can try downloading the installer if you didn't keep it and create a bootable Mojave USB installer, boot from that and try installing it to your external drive.

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Answer 6

Old Toad

Level 10

215,760 points

Sep 30, 2018 9:08 AM in response to richardmclarke

Are you using any of the WD software that usually comes with WD drives? If so, don't. It's not needed. Uninstall and test again.

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Answer 7

macjack

Level 10

111,242 points

Sep 29, 2018 8:45 AM in response to richardmclarke

I've seen several threads where Mojave has been downloaded to an external hard drive without issues. I'm not sure why yours would be an exception. But you can try the bootable installer route as dialabrain suggests.

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Answer 8

léonie

Level 10

200,645 points

Sep 30, 2018 10:09 AM in response to richardmclarke

As I can see, the file system format of your external SSD drive is McOS Extended (Journaled).

Which system is currently installed on this drive?

Perhaps the Mojave installer wants to upgrade the SSD drive to APFS and can't.

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Answer 9

turingtest2

Level 10

278,263 points

Sep 30, 2018 11:22 AM in response to richardmclarke

Oddball suggestion, but why not make a new empty Photos library and Designate it as the System Photo Library in Photos, then try again?

tt2

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Answer 10

Sep 29, 2018 12:13 AM in response to macjack

Thank you. I installed Omni DiskSweeper and it showed I have about 150GB of space.

I have also rebuilt the spotlight index however the problem still exists.

I go to about this mac / storage and it shows the SSD is full. I click manage and it shows it is full of photos.

The photos clearly aren't on the SSD.

Any thoughts?

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Answer 11

Sep 29, 2018 8:24 AM in response to dialabrain

Thanks. That seems to have solved the storage display error.

However I still can't install Mojave it says "the target disk is too small for this operation. Quit the installer to restart your computer and try again" even though there is 150GB free.

Any ideas?

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Answer 12

Sep 30, 2018 12:52 AM in response to Old Toad

Still no luck.

I created a USB boot drive and booted from that and it came up with the same error.

I booted into safe mode and installed it from there and still no luck.

Any other ideas? or should I do a clean install on the SSD drive?

Thanks for all your help so far

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Answer 13

dialabrain

Level 10

136,127 points

Oct 3, 2018 3:24 AM in response to richardmclarke

FWIW, your issue isn't because the drive is not formatted as APFS. The Mojave installer would convert it itself. Not sure what the issue is but, I just installed Mojave on a WD 2TB My Passport Ultra without an issue.

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