I tried to run chkdsk as suggested but got a message that chkdsk could not open the volume for direct access. Should I use chkdsk /f instead? I looked at the log produced by the exec and it didn't have any information in it relating to the latest chkdsk run. The latest entry was:-
------< Log generate on 29/12/2015 09:12:32 >------
Category: 0
Computer Name: Paul-Laptop
Event Code: 26212
Record Number: 953099
Source Name: Chkdsk
Time Written: 12-28-2015 @ 13:05:51
Event Type: Information
User:
Message: Chkdsk was executed in read-only mode on a volume snapshot.
Checking file system on G:
The type of the file system is NTFS.
Volume label is My Passport.
WARNING! F parameter not specified.
Running CHKDSK in read-only mode.
49984 file records processed.
0 large file records processed.
0 bad file records processed.
0 EA records processed.
0 reparse records processed.
53316 index entries processed.
0 unindexed files processed.
49984 security descriptors processed.
Cleaning up 15 unused index entries from index $SII of file 0x9.
Cleaning up 15 unused index entries from index $SDH of file 0x9.
Cleaning up 15 unused security descriptors.
1667 data files processed.
CHKDSK is verifying Usn Journal...
34258008 USN bytes processed.
Usn Journal verification completed.
Windows has checked the file system and found no problems.
1953480703 KB total disk space.
372045080 KB in 48248 files.
20740 KB in 1668 indexes.
0 KB in bad sectors.
209359 KB in use by the system.
65536 KB occupied by the log file.
1581205524 KB available on disk.
4096 bytes in each allocation unit.
488370175 total allocation units on disk.
395301381 allocation units available on disk.
-----------------------------------------------------------------------
- which appears to have come from when I connected an external drive for backup. (I am running Vista) The full log is at
https://drive.google.com/file/d/0B7PqpaxIdCMHa0Jxc2xNVUoyaEk/view?usp=sharing (not pasted here as it is 172KB)
Incidentally, I used to run a registry cleaner (either CCleaner or Advanced System Clean) and have now stopped doing that in case that was the cause of my problems. Since stopping doing this I haven't had any problems. Could one of those utilities have caused my problems?