Time Machine backs up to one profile, and reads from another

Question

I have been running backups with Time Machine, for about 2 months now. Until now, I've never really looked closely at what comes up when I run TM.
Today I've found that when the app is run, I can only jump back to states from the first two days that were backed up - 25th and 26th August, even though I've seen and forced backups throughout these 2 months.
When I look in the "Backups.backupdb" folder, there seem to be two computer profiles for backing up. They are both the name of my computer, with the second one having a number 2 appended to the folder name.
Inside the number 2 folder, I can see all of the backups performed since 26 August. It seems that my Time Machine is backing up to folder 2, but reads from folder 1!
I don't mind deleting the whole TM setup, and starting again. In some ways I prefer it, as I want to partition this drive (but not format it), and place the TM backups on a separate partition. I'm just a little cautious of deleting backups.backupdb folder, or anything inside this.
Does anyone know what's happening, and can I delete the "backups.backupdb" folder, or one of these backup profiles inside without stuffing things up?
Cheers

Answer 1

You only have one Mac backing up to the Time Machine disk?
If so, then at some point, Time Machine lost track of the first set of backups and began a second set. Do you recall any event a day or two after you began using Time Machine that might explain this? Perhaps a system crash or swapping drives somehow? Something cause Time Machine to abandone the first set and start fresh.
If you are going to repartition the drive, here is some advise regarding how to proceed...
*_How Should a Time Machine Hard Disk be Prepared?_*
For Time Machine to work properly, the hard disk must be formatted “Mac OS Extended (Journaled)” and its’ Partition Scheme should be either GUID or Apple Partition Map.
Time Machine is incompatible with disks partitioned as Master Boot Record (MBR). Unfortunately, this describes nearly every hard drive you can buy because MBR is a Windows partition scheme. (Naturally, this DOES NOT apply to Apples’ Time Capsule.)
For some, Time Machine begins to perform as expected with a new external hard disk. But then the initial full backup or subsequent incremental backups fail. The user only later discovers the hard disk was still partitioned as Master Boot Record (MBR).
One article on Time Machine made this observation: “Virtually everybody will have to open Disk Utility and repartition the disk as APM or GUID. It doesn't really matter which one because the Time Machine disk will not be bootable anyway. APM allows a disk to boot a PowerPC, GUID allows the disk to boot an Intel processor but both are easily digestible by Time Machine on either kind of processor.” [http://www.girr.org/mac_stuff/backups.html]
It’s been recommended by many here that your reserve +at least+ double the size of your primary hard disk, that way Time Machine backups have room to grow as the size of your data grows. Additionally, the more space you give Time Machine the more history it can preserve. The less space you reserve for Time Machine the sooner older backups & deleted items will disappear.
One poster recommended this regarding multiple partitions: “If you do create multiple partitions (half and half would be a good place to start), make sure you use the first partition for Time Machine, and the second for your own stuff (the first one will be on top in the graphical representation shown in Disk Utility; you'll understand when you see the partition tab). This way, you can expand the Time Machine volume at any later time by deleting the second partition. Disk Utility allows this dynamic re-sizing of volumes, but volumes can only be expanded toward the end of the drive, when a volume that comes after is deleted to create the room.” [http://discussions.apple.com/thread.jspa?threadID=1712437&tstart=0]
Procedure
Connect the hard disk you wish to use for Time Machine backups.
Launch Disk Utility.
It will appear twice in the pane on the left. (Make sure you recognize that it is different from the 2 icons that represent your Macs' internal drive.) The upper entry represent the device as a whole, including the controller inside. The lower entry represents the hard disk contained within the device.
Click on the upper icon of the external hard disk.
Select the "Partition" tab.
For "Volume Scheme" choose "1 partition". (Choose 2 partitions if you intend on storing other data on the disk besides your Time Machine backups. Ensure that the two partitions have different names.)
Name the disk.
Format should be "Mac OS Extended (Journaled)".
Click "Options".
Select either GUID or Apple Partition Map. (See above for significance)
Click "OK".
Click "Apply". Then click “Partition”.
Once the external hard disk is repartitioned, select it again in Time Machine preferences and use it for your backups. If you chose to create 2 partitions, then select the first partition for Time Machine backups, and the second for additional files/folders.
Let us know if this was helpful.
Cheers!