Not enough room on Time Macine? But there is!?

Hi,

I got a new Macbook Pro and transferred everything over perfectly with Time Machine from my external H/Drive. Now when I try and back up Time Machine on my new computer it won't let me saying it is full. It's not full because I only have 320GB H/Drive on my computer and the external is 500GB!?
Is it somehow trying to double up on files from my old computer? So save everything twice?
I would be happy to just wipe my external and start fresh but it seems like that is even a difficult process, is there nothing in TM that will allow me to clear all and start fresh?
Not sure what to do here, any help would be great, thanks.

Hello, welcome to M-F

Time Machine keeps versions of your data, Hourly backup versions for the past 24 hours,Daily backup versions for the past week, and weekly backup versions for all past months till the external HD is full by which time it will ask to delete the oldest versions.
While it doesn't keep the whole HD mirrored just the files that have changed, it may be that depending on how long you have been using TimeMachine it can really be full.
You can see how much free space the TM HD has in the Finder or Disk Utility,

If you really want to start over here's how to do it.
Open Disk Utility in the Utilities folder and select the HD that TimeMachine backs up on, and under the Erase tab, erase it as Mac OS Extended (Journaled).

Here is what I think is happening. Time Machine is trying to start a new series of backups. It doesn't care that the data is the same the machines are different. How does it know this?

A little-known fact about Time Machine is that it depends on the MAC address of a computer to tell one system from another. This means that if you have your Mac repaired with a new logic board, or replace your system with a new one, you can't resume backups where you left off. If you know of the problem, though, it's not very hard to fix. You need to re-pair the backup to the new logic board's MAC address. Further complicating matters is the ACL which prevents you from changing the system ID information.

Click to expand...

You can find more information in this thread 10.5: Repair Time Machine after logic board changes - Mac OS X Hints. I know it talks about logic board replacement but that is essentially what has happened in your case. There is a fix posted in that rather lengthy thread.

You might want to give the support guys for this software a shout. Unless I misunderstand what it is doing it might be just what you need. Back-In-Time (vs Time Machine).

In case you're wondering I have no connection with them whatsoever.

Oo, good one Slydude. Hopefully that is the problem and the solution.

Thanks. That site is among about a half dozen or so that I load daily via Automator when I first boot the machine. Usually a lot of really good information though sometimes it goes over my head.

Thanks, I just erased all and started over, didn't realise it was so easy to do.