Outlook suddenly failed to open stating it could not open the default e-mail folder, the file :\.......\documents\outlook files\outlook.pst could not be opened.

I have run scanpst.exe which suggested there was a fault, repaired it and now if scanpst is run, no fault is found. However, outlook still will not open the default e-mail folder.

I thought it might be due to AV software, but it isn't.

Any ideas folks as to where I go from here?