This guide shows you how to clean install macOS Catalina so you can leave all the problems in macOS Mojave behind and start fresh. This can help you speed up an old Mac, gain some drive space, and fix some issues or bugs.
A clean macOS Catalina isn’t for everyone, but if your Mac is a few years old, this might be a good time to try a fresh install and clean up the trash you’ve left there over the years. Whether you upgrade or do a clean install, you still need to be prepared. Here’s what you need to do before installing macOS Catalina.
Follow the steps below to perform a clean install of macOS Catalina on your Mac. Note that there are some good reasons not to install macOS Catalina yet, and there are a few macOS Catalina issues.
Should I Clean Up macOS Catalina?
Not everyone needs to do a clean install of macOS 10.15, but if you’re having macOS Mojave issues, it can help you start fresh and usually frees up space on your SSD or hard drive.
A good rule of thumb is if your Mac is over four years old and you haven’t done a clean install, it’s wise to consider this if you have any issues. If your Mac is newer, you probably don’t need to do a clean install.
If you do a clean install, it will delete everything on your Mac. You need to make absolutely sure that your photos and files are backed up and that you have access to the app installers you need. You can choose to restore from a Time Machine backup, but the point is to start from scratch.
How to Clean Install macOS Catalina 10.15
Download the macOS Catalina installer as normal.
You need to download the macOS Catalina installer from the App Store, you need a 16GB or larger USB drive that you can format and install the update on, and you may need a USB C adapter depending on your MacBook model.
Start the macOS Catalina download from System Preferences or find it in the Mac App Store. Once complete, do not install the update yet.
Create a macOS Catalina installer on the USB drive.
- Connect your USB drive to your Mac. The application will erase and format the drive.
- download Disc Creator 2 and then click on Application.
- Select the USB drive from the drop-down menu.
- Click Select Installer if it’s not already selected and select the macOS Catalina installer.
- Click Create Installer.
- Click Erase disk.
- Wait for a confirmation that this is complete.
You now have a bootable macOS Catalina installer that you can use to perform a clean install of macOS Catalina. The next step is to reboot the Mac and boot into macOS Utilities so you can wipe your drive and install macOS 10.15.
- Drop In USB Installer.
- Shut down your Mac.
- Restart your Mac while holding down the Option key.
- Click Install macOS Catalina.
- Now click on Disk Utility.
Erase your driver and then install macOS Catalina.
- Click on your Mac hard drive, then click Erase. Use the default options here.
- Name your hard drive Macintosh HD and then click delete.
- Wait for the driver to be deleted.
- Click Install macOS.
This will start installing macOS Catalina on your Mac. Since it’s already downloaded, expect this to take about 30 minutes; this is faster than the standard macOS Catalina load time. Once the setup is complete you will be able to complete the new Mac setup and start using your Mac.
