With reference to my last comment, I have now found which file was repaired. It is likely an old root.disk I had deleted from Ubuntu (after creating a new bigger root.disk).
The strange thing is that Windows 7 did not even show the existence of the folder "found.000" until I had changed the setting in Windows Explorer to not "Hide protected OS files". Even then I couldn't enter the directory except from an Administrator command prompt:
C:\>cd found.000
C:\found.000>dir
Volume in drive C is OS
Volume Serial Number is B4B7-99A8
So, in my case, it was the intentional deletion of a large file from Ubuntu that (some time later) was detected and recovered by Windows. Not any corruption of the root.disk itself through normal use of Wubi. Which is good.
With reference to my last comment, I have now found which file was repaired. It is likely an old root.disk I had deleted from Ubuntu (after creating a new bigger root.disk).
The strange thing is that Windows 7 did not even show the existence of the folder "found.000" until I had changed the setting in Windows Explorer to not "Hide protected OS files". Even then I couldn't enter the directory except from an Administrator command prompt:
C:\>cd found.000
C:\found.000>dir
Volume in drive C is OS
Volume Serial Number is B4B7-99A8
Directory of C:\found.000
25/06/2011 01:41 PM 15,000,000,000 file0000.chk
1 File(s) 15,000,000,000 bytes
0 Dir(s) 207,932,407,808 bytes free
C:\found.000>
So, in my case, it was the intentional deletion of a large file from Ubuntu that (some time later) was detected and recovered by Windows. Not any corruption of the root.disk itself through normal use of Wubi. Which is good.