How To Download Mojave To External Hard Drive ((EXCLUSIVE))
Partenia Urtiaga
Thanks for reaching out on the Apple Support Communities. I understand you're having trouble with your external hard drives no longer mounting automatically when you connect them to you iMac. I know how important it is to have access to the data on your external hard drives. Thank you for letting us know that this began after you upgraded to Mojave. Be sure that you're running the latest version of Mojave, first. You can do this by going to the Apple Menu > System Preferences and it will show you if there are any updates. You can also go to System Preferences > Software Update. This is where you'll find the macOS Mojave updates.
Probably doesn't make any difference whether I run it in recovery mode or fully booted since they are external. It's been a while since I have run recovery/verification on my external drives. Have never done that before, however haven't had any issues until after the upgrade.
I am trying to use a USB stick Mojave installer I created with "Install Disk Creator" to install a clean copy of Mojave on an empty external hard drive (USB 3), and the install won't complete. Instead I get a folder named "macOS Install Data" on the external drive. I've tried reformatting the drive as APFS as well as the old Mac OS Extended, and have tried installing from the Recovery mode of my computer (a Mac Pro 5,1 running Mojave with a Metal graphics card flashed for Mac), and have the same problem no matter what I do.
Each time you boot the macOS installer make sure to launch Disk Utility and erase the whole physical external drive as GUID partition and MacOS Extended (Journaled). You may need to click "View" within Disk Utility and select "Show All Devices" so that the physical drive appears on the left pane of Disk Utility. Then and only then select the "Reinstall macOS" option and select the external drive. Erasing the whole physical drive is critical since external drives come from the factory partitioned & formatted for use with Windows and may not be compatible with macOS until the whole physical drive has been properly erased using Disk Utility.
Now perform a PRAM Reset (hold the PRAM Reset for at least three chimes). This will clear out all stored boot options from the NVRAM that may inadvertently cause the Mac to boot from the wrong media. Now Option Boot the macOS USB installer (hold the Option key immediately after the Startup Chime) and select the orange icon. You should now be able to select the external drive as the destination for the Mojave installer.
If you still have a problem, then please state exactly what error message is and at what stage this error occurred. You may want to post a picture of the error message. If you only have an "macOS Install Data" folder, then it means the installation failed at some point. If it failed during the second install stage after a reboot, then you may be able to see what happened by examining the installation log file which will be found on the external drive (perhaps the log will even exist if it failed on the first stage, but I'm not sure).
Do NOT use Recovery Mode at all during this procedure as it will only confuse things and Recovery Mode can easily fail due to any number of impossible to troubleshoot networking and Internet issues. Like I said before Macs are very picky about the USB sticks (and even drives) used for booting plus the quality of USB sticks is extremely poor so make sure to try using two different USB sticks (especially different brands). It is also possible the external hard drive you are using as a destination for Mojave is not compatible as a bootable Mac drive (Macs are very picky) or maybe the external drive is disconnecting during the install or perhaps the external hard drive is bad. You can attempt to check the health of the external drive by using DriveDx and posting the complete health report here using the "Additional Text" icon which looks like a piece of paper. You will need to install a special USB driver, but even with this special USB driver there is no guarantee that DriveDX will be able to access the external hard drive's health information since may USB controllers found on external drives do not allow for the necessary communication even when using the special USB driver.
To make sure your current internal drive is not interfering remove the internal drive from the Mac Pro (easy to do in the Desktop tower, just make sure the computer is powered down & unplugged when inserting or removing the drive). I'm not entirely sure if the Mojave installer will install to the external drive without a properly partitioned & formatted internal drive, but it is definitely worth a try if all else fails.
The installer begins to copy files to the external hard drive, then the process fails for some reason before the installer reboots the Mac. There should be some kind of error message that may contain useful information even if the process is unable to proceed. If there is no error message, then what actually happens the moment the install fails?
Most likely your Mac or the USB stick or the external drive has a hardware issue that is causing the install to abort. Or some other external factor is affecting your Mac during the installation process. Don't overlook the fact that you may have a bad data cable or USB port either. Sometimes the smallest seemingly insignificant item is the source of problem.
I tried searching online for similar issues and was unable to find anything similar (only performed a quick search). I believe I have seen this happen with one of our organization's Macs leaving just an "Install macOS Data" folder (also saw a couple of other weird things on a few other failed macOS installations), but I was not the one who had initiated the failed installs (plus our installs are performed a bit differently) so I have no idea how or why it failed since there were no installation logs available that I could locate for the failure which left behind just the "Install macOS Data" folder. I either found no hardware issue and was able to successfully install macOS from Internet Recovery Mode/USB stick several times or I found the destination drive was bad (I found a bad destination drive with only two of the failed installations).
I think you will need to take your Mac and the external drive to an Apple Store or an Apple Authorized Service Provider to be examined so they can assist you with installing macOS to the external drive. This may be a situation where a first hand observation of the installation is needed in order to detect what may be causing the failure.
I am not booting into Recovery Mode to use the USB Installer. I am selecting it with the Startup Manager, as you say. But there is another alternative, which is to boot into Recovery Mode, and use the built-in MacOS installer. That gives me the same result-- a folder named "macOS Install Data" on my external hard drive.
I followed all of your suggestions to a T and am still getting the exact same result. No error message, but the install does not complete, and I am left with a "macOS Install Data" folder on my external drive. There is a log called "ia.log", but I don't know how to make heads or tails from it. The drive is perfectly healthy. I even tried another drive and had the same problem. There must be another way to go about this.
I've installed Mojave fresh, direct using an Apple-downloaded installer 4x now on 2 brand new, freshly formatted Seagate 2TB drives as well as a partition on another reliable non-Seagate drive. Drives were formatted Mac OS Extended journaled and GUID and connected directly to usb on specced-out Mac Mini 2012 running Mavericks. In all cases install was smooth and ended with booting to fully operational Mojave installs on external drives. All good so far.
Reboot to the original on-board OS (Mavericks) either by selecting in prefs>startup disk or by shutdown and disconnect/reconnect external drive and the new Mojave partition doesn't show as an OS or on the desktop or anywhere. In Disk Utility it's now greyed out and renamed to disk1s2. A 2nd non-OS partition on the same external drive shows up as normal, just the Mojave partition has gone AWOL and doesn't appear in prefs>startup disc either.
So I want to install node.js on my external hard drive so I can do some batch processing on images for my website. I was following this article and there's a section for converting images to webp with node. I've been trying to do that, but I keep having problems that I think are related to most of my files being on a 1tb external hard drive b/c my mac only has 250gb of space ($$ reasons). At the same time, I'm still confused about node.js and npm and how it all really works - as soon as I think I understand I find more info that puts me back at square one. I've really tried to do my own research re: errors that come up when installing node.js but it'd be really helpful if someone could simplify this process for me and help this 'lil noob who just wants to learn something new and more efficient.
tl;dr - My goal is to install node.js to process some images on an external hard drive on my mac and I want to do it smoothly and actually understand what's happening b/c the influx of information I'm getting from researching on my own is confusing me more than helping me :')
You may be running into a new security feature. I believe it is present on Macs that have a T2 chip. By default, it prohibits booting from external drives. You can change that by following the instructions in this support document.
f5d0e4f075