Problems starting a completely fresh total backup on Time Machine - Help!

Question

I recently had an iMac which refused to boot. I reinstalled from a combination of Time Machine restore and the original system disc. It still took 7 hours to get all the preferences and odd programmes which didn't seem to restore back to working order.
I wanted to do a complete Time Machine backup starting from scratch using a fresh 500Gb ext hard drive. I did the following as suggested:
1.On the Time Machine Preferences window, click the Options button. Note anything in the exclusions box, then click Cancel to return to the main window. Note the settings of other option(s), then turn Time Machine OFF and quit System Preferences.
2.If you're backing-up to an external HD, eject, disconnect, and power it off for a few moments, then reconnect it.
3.Delete the file /Library/Preferences/com.apple.TimeMachine.plist (in your top-level Library folder, not your home folder).
(You may have to navigate to it; a Spotlight search won’t show it, and a Finder search won’t, either, unless you include System Files. If you have a problem finding the file, see item #A7.)
4.Go back into Time Machine Preferences, re-select the drive, re-enter any exclusions and other options you noted in step 1. Note that the oldest and latest backup dates won't appear on this window until the next backup is done.
5.A 120-second countdown to a backup should appear. If you close the window, it should begin immediately.
The Mac HD has a used space of 150 Gb, but before the new TM backup started it counted thousands of files which were 'excluded' even though I hadn't asked for this. When the actual backup started it was saying that it was backing up a total of 68 Gb. Surely this can't be correct. I know that TM automatically omits a number of system files but surely not 82GB worth? I have a feeling that despite trashing com.apple.TimeMachine.plist it may be picking up from where the 'old' external hard drive (which contained the previous total TM backup) left off?
All I want to do is start afresh using this new 500Gb EHD but ensure that the whole of drive is backed up. How do I do this or is there a better way of backing up the whole drive on a regular basis?
Thank you.

Answer 1

Colin Cadle wrote:
I recently had an iMac which refused to boot. I reinstalled from a combination of Time Machine restore and the original system disc. It still took 7 hours to get all the preferences and odd programmes which didn't seem to restore back to working order.
I wanted to do a complete Time Machine backup starting from scratch using a fresh 500Gb ext hard drive. I did the following as suggested:
You didn't really need to do all that. Those instructions (from #A4 in [Time Machine - Troubleshooting|http://web.me.com/pondini/Time_Machine/Troubleshooting.html]) are for a "full reset" of Time Machine, such as, when there's a problem with the preferences file, to get Time Machine to continue backing-up to existing backups.
When you back up to a new or erased drive, Time Machine starts fresh.
The Mac HD has a used space of 150 Gb, but before the new TM backup started it counted thousands of files which were 'excluded' even though I hadn't asked for this.
When you did this, was the old TM drive connected? If so, that's probably what was being excluded. Time Machine will automatically exclude the +*currently selected+* backup drive, but if it finds a different volume containing TM backups, it won't exclude the entire drive, since there might be other data on it; so it excludes just the backup files on the drive. Your best bet is to eject and disconnect the old drive; otherwise, specifically exclude it.
When the actual backup started it was saying that it was backing up a total of 68 Gb. Surely this can't be correct. I know that TM automatically omits a number of system files but surely not 82GB worth?
It's possible. Depending on exactly went wrong, and exactly what you did, some things may not have been restored to the proper places, or the sizes being reported are inaccurate.
Exactly what did you do? Did you, for example, select your internal HD in the "Star Wars" display, and tell TM to restore it?
How much data was on your system before all this started? Was it about 150 GB, or was it more like 70 GB?