Having issues with Time Machine backups on your new external hard drive?
Well the solution to Time Machine Error Code -43 is brought to you by WBTCZN on the Apple Forums. "I stumbled on to the answer...I was in System Preferences to do
something else and saw the Time Machine icon. I opened that one up and
was able to change the drive...it was pointing to my FAT32 drive
instead of the new drive."