Backblaze backs up individual files to an unlimited size depending on settings (the 4 GB default for some installations can be increased to Unlimited in the settings). If your computer's system hard drive has less than 1.1 times the size of the largest file scheduled to be backed up left in free space, Backblaze will not backup that file and alert the user. To enable these files to be backed up, please free up enough space on your computer for 1.1 times the size of your largest single file.
Alternately, a Temporary Data Drive is available in the Backblaze settings. If you have a secondary drive with more free space than your boot drive, you can set Backblaze to write to that drive rather than your boot drive.