Why won't system disk defragment?

[NorthernGobshite]

My laptop system disk will not defrag. I have tried numerous times but it just won't. Its 11% fragmented if thats any help?

It just takes bloody hours, that's all. Best to do it in safe mode, which you can generally get to by rebooting and tapping F8 whilst it's starting up. A start up menu will appear from which you will choose safe mode. Run defrag and leave it till it's finished. It'll still take a good few hours.

No, it won't do it at all. It says it is going to, then just goes back to saying 11% fragmented. Works fine on other disks etc.

Try a disk cleanup first

There's usually something that will be running in the background that will keep prompting defrag to restart - hence its always being at 11%. Try closing down everything you don't need to run via CTRL-ALT-DELETE/Task Manager, or run it in safe mode, which keeps all programs down to a minimum.

Did you try safe mode?

You don't say which operating system you're using, but defragmentation will work most efficiently when there's a reasonable amount of free space on the drive, the more the better.

If you're using a version of Windows the built-in defragmenter isn't that great, so you might try a third party one (like this). Bear in mind also that some system files can't be effectively defragmented while they're in use (more recent versions of Windows are better with this as defrag can be run on reboot) so using a bootable system utilities disk might be another answer.

Windows 7
Have downloaded a disk defrag which seems to have worked a little better. IT friend says not to worry so thanks all!