Why True Image create a full backup instead of increamental backup?

Hi,

In my backup setting, I set to create a full backup only after 30 incremental backups. However, currently I only have 6 incremental backups. When I try to make a new backup, it always try to create a full version. Why?

I make a test by changing the backup schema from 30 to 31. And this time it create an increamental backup again.

It seems the problems come from the follow:

1. I backup every week to a hard drive.

2. The hard drive is full.

3. I replace the hard drive with a new one.

4. I continue backup with the original backup profile.

5. Since there are no full version in the new drive, it create a full backup.

6. But it seems the backup profile contain a counter which record the total number of increamental backups. And it is likely that the old drive contains 24 increamental backups already.

7. Thus when there are 6 increamental backups in the new drive, it will start a new full backup.

So, my question is, how to continue using the old backup profile, but start a new backup sequence when switching to a new hard drive?