Use an External SSD As Your Startup Disk With Your iMac Or Mac Mini

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No matter your startup drive needs – more space, improved performance or both – using an external SSD as your main startup device is an accessible and straightforward option.

An SSD uses electronic storage that does not lose data when your Mac shuts down, and also uses less power than hard disk drives.


Installing a modern external SSD as your startup disk can significantly boost the performance of an iMac or Mac mini, turning it from being slow as hell into one that meets most users’ requirements. SSDs don’t contain moving parts so are much less susceptible to physical malfunction than HDDs are.

Before connecting an SSD, ensure it can store all your media and data files. Depending on your budget, portable SSDs come in capacities ranging from 50GB (ideal for casual use with numerous smaller Word documents) up to 2TB for extensive media libraries and large data files.

When purchasing an external SSD, be sure to look for models compatible with macOS such as APFS or HFS+ formats, USB 3.1 technology and startup disk capabilities – Apple sells an external SSD that meets these criteria – the LaCie Mobile SSD Secure USB-C Drive – Gray – Apple.

Once you’ve chosen an SSD, connect it to an available port on your iMac and launch Disk Utility (applications > Utilities). Follow the prompts for formatting it into a stable and bootable startup disk for your iMac or Mac mini.


Solid-state drives (SSD) can be an efficient way to store photos, music videos and more while moving large files between computers. Small enough to easily transport and fast loading times provide fast data transfer rates over their long lifespans – however if selling it or giving it away it’s essential that it be erased securely first before use by anyone else.

Kingston’s SSD Manager or other secure erasure-compatible software should be used to enact this action, as clearing drive partitions will completely erase all data stored on an SSD. To protect yourself and ensure all of your information remains in tact, if erasing is essential to keeping data stored on an SSD safe – but remember that clearing will remove everything stored there, so make sure you back it up first before taking this step.

Your internal SSD from either your laptop or desktop computer can become an external storage device if it features a USB-C connector and is compatible with Mac computers. There are specialized enclosure accessories designed specifically for this use; you could purchase from major brands or create your own using an older internal SSD and an adapter cable from USB-C to A.

When you are ready to format an external SSD to work with an iMac or Mac mini, open Disk Utility on your Mac and select it from the list of devices. This will expose any hidden partitions on the SSD so you can delete them – once complete you can connect your drive and launch macOS onto it.


An external SSD can give your aging iMac or Mac mini an impressive performance boost, thanks to its superfast SSDs that can run up to 20 times faster than their hard drives. An SSD allows your computer to boot faster and run programs more quickly – both important factors when keeping up with daily demands.

Your hard drive or SSD could eventually wear out and stop functioning completely or show signs of malfunction, making having a backup plan essential.

If you own an external SSD, it can easily serve as your startup disk in case your internal drive starts acting up or no longer responds, providing an easy solution should your internal drive stop responding and disrupting work. Switch back over and keep working.

To protect all your data effectively, it’s essential that you create an adequate backup using a tool such as Disk Utility. Furthermore, creating a bootable USB installer of macOS for troubleshooting and recovery purposes should also be a part of your plan.

To clear out nonvolatile random-access memory (NVRAM), restart your Mac while holding down Command-R during rebooting. Once desktop comes up, macOS Utilities window should appear prominently in the middle of your screen.


An external SSD drive can make a fantastic choice to upgrade a failing or slow internal disk in your Mac, offering large libraries shared between computers or full system backups for recovery should something go wrong. Plus, its lightning-fast speeds mean it runs programs nearly as quickly as RAM!

If your Mac doesn’t recognize an external drive, make sure it is securely plugged in and that its cable works properly. If that fails, try plugging it into a different USB port or hub on your iMac or Mac mini or it could even be that the connector on your drive has become dirty or misalignled, which may create short currents which prevent recognition by your computer.

If you use an SSD as your startup disk, be sure to update to the most up-to-date version of macOS for optimal stability and performance, minimizing risks such as file corruption. Also keep up-to-date with security updates to help safeguard against malware threats that may pose risks; failing which you risk data loss or other problems associated with being behind on updates.