Unable to interpret time or date error

When I select tools - preferences I get an error saying “Unable to interpret time or date”, I press ok then get “Notes Error - field didn’t pass validation formula”. Pressing ok again takes me into the menu. Under calendar - Scheduking I can see Mon-Fri with error in the fields. I have checked pc time and date which are ok, for some reason I cant change the fields as it pops up an error msg each time I add the times in.Unable to press ok to save changes as first error pops up again. As this is a director’s machine I would love some assistance.Thank you

Subject: Unable to interpret time or date error

Different date-time format of your pc to the server may cause this error. check if both are same.

Subject: RE: Unable to interpret time or date error

That did not work… Any other ideas… ?