It's always wise to back up your data before any operating system update. But that's especially true for owners of Mac computers installing the macOS Big Sur upgrade, which seemingly pays no regard to the amount of free storage space before initiating the update process, risking data loss for users.
The problem with Big Sur is that the update process is being launched without the installer checking whether there's enough free space in the Mac's internal storage. Several specialist news sites are reporting that the update is being initiated even if there's less than 1% available storage, which can lead to data being corrupted. In the worst case scenario, the update can fail, preventing the hard drive from rebooting and leaving users unable to access their data.
While tech-savvy users know that it's always a good idea to back up data -- whether or not storage space is low -- before any system update, too many users still get caught out.
MacOS Big Sur was launched in November 2020, but if you haven't yet installed this version on your Mac, be sure to back up your data just in case. The easiest way to do that is to use Time Machine, the tool available in macOS, with an external hard drive.