Before trying more intrusive steps or potentially wasting time clearing files that may not need to be removed, checking for the actual disk space available helps to confirm whether the error message corresponds to the real issue. This is important because error messages can sometimes be misleading, and assuming they are correct without verification can lead to unnecessary steps. If ample disk space is indeed available, troubleshooting can proceed towards other potential causes such as file system errors, corrupted update files, or software conflicts. On the other hand, 'Disabling antivirus software' and 'Running a disk defragmentation' are not immediately necessary and may not address the root problem of the update failure. 'Performing a clean boot' may address other conflicts that prevent the update from installing, but this does not directly address the error message indicating insufficient disk space.