the updates run normally for about four days then the same problem recurs.
That begs the question, what is happening on that fourth day? Are you by any chance using Registry Cleaners or rival security software perhaps?
Is Windows 7 with SP1 or without and does it have IE9 installed regardless of your browser preferences?
What version of the software is this? Open it and click 'About'.
You could try running the Virtual Technician to see if it finds and fixes any issue: http://mvt.mcafee.com/
If not then Technical Support is available free of charge by phone or online chat through Useful Links at the top of this page.
Thanks for your suggestions.
My operating system is Windows 7 with Service Pack 1.
My browser is IE 9.
McAfee Security Centre version is 11.6.
I have tried Virtual Technician, which identifies the problem but cannot repair it (although you would think that a corrupt DAT file is precisely the sort of thing Virtual Technician ought to be able to repair).
At present I have updated the DAT file manually using Superdats installation, and updates are now occurring again (but for how long?).
The only thing I can think of that runs approximately every four days is Windows Defender update, but I have always had that running and it has never caused problems. I might, however, stop those updates for a while and see if it makes any difference. (I do not use registry cleaners.)
Incidentally, I have the same version of McAfee installed on an old computer (Windows XP with SP3, IE8) and the updating problem has not occurred on there (at least not yet).
So you're not running Registry Cleaners? I wonder what is corrupting the DAT's? Windows Defender works fine in my Windows 7 too so don't worry about that. Should you ever need to reinstall McAfee it will disable WD but you can always reactivate it.
Anyone reading this with Windows 8, that does not apply to you because Windows Defender is a totally different piece of software in Windows 8 and includes antivirus, so it is disabled by McAfee for a good reason.
You could try uninstalling via Control Panel, running MCPR cleanup (see Useful Links at the top of this page), reboot and reinstall from your online account.
Or contact Technical Support and have them start troubleshooting this issue. It's free by phone or online chat and also linked under Useful Links.
I did go through the full reinstallation procedure as described above a few days ago, and updates then started working again for a while, but stopped after a few days.
Having got them working again now I shall monitor the updates closely and try to spot exactly when they stop again, and see if the stoppage can be related to any obvious activity on the computer.
I have been monitoring the problem carefully now for over a week and am still finding that updates run all right for a few days then suddenly stop and will not run either automatically or manually.
One new thing I have discovered is that simply restarting the computer appears to clear the problem, so it is not as laborious as I originally thought to get the updates running again (at least temporarily), but I still cannot work out what is triggering the problem in the first place. I am unable to relate it to anything I have done to the computer - updates can be working all right last thing before I go to bed, then not working again first thing the next morning.
But if I can get round the problem by just restarting each time it happens I suppose I can put up with it.