You can definitely run an iMac from an external hard drive. There are a few different scenarios where running your iMac from an external hard drive can be beneficial.
One common scenario is when your internal hard drive is running out of storage space. If you have a large collection of files, such as photos, videos, or music, it can quickly eat up the available space on your internal drive. By running your iMac from an external hard drive, you can free up space on your internal drive and keep your files accessible.
Another scenario where running your iMac from an external hard drive can be useful is when you want to test out a new operating system. Installing a new OS on your internal drive can be risky, as it may have bugs or compatibility issues that could disrupt your workflow. By installing the new OS on an external drive, you can safely test it out without affecting your main system.
To run your iMac from an external hard drive, you will need to follow a few steps. First, you will need to connect the external hard drive to your iMac using a USB, Thunderbolt, or FireWire cable, depending on the available ports on your iMac and the type of external hard drive you have.
Once the external hard drive is connected, you will need to format it to be compatible with macOS. This can be done through the Disk Utility app, which is located in the Utilities folder within the Applications folder. Simply select the external drive, choose the Erase option, and select the appropriate format (usually Mac OS Extended or APFS).
After formatting the external drive, you will need to install macOS onto it. This can be done by accessing the macOS installer, either by downloading it from the App Store or using a bootable macOS installer disk. During the installation process, you will be prompted to select the destination drive, so make sure to choose the external drive.
Once the installation is complete, you can restart your iMac and hold down the Option key while it boots up. This will bring up the Startup Manager, which allows you to choose the startup disk. Select the external drive and your iMac will boot up from it.
Running your iMac from an external hard drive can provide a number of benefits, but there are a few things to keep in mind. First, the speed of the external drive can impact the performance of your iMac. If you choose a slower drive, you may experience slower load times and overall system performance. It’s recommended to use a high-speed external drive, such as a solid-state drive (SSD), for the best performance.
Additionally, keep in mind that your iMac will need to be connected to the external drive in order to use it as the startup disk. If you disconnect the drive or it becomes unavailable, your iMac will not be able to boot up.
Running your iMac from an external hard drive can be a useful option in certain situations, such as when you need additional storage space or want to test out a new operating system. By following the necessary steps to format the drive and install macOS onto it, you can safely run your iMac from an external drive and enjoy the benefits it provides.