Problem deleting specific history from safari
My Safari history records puts some browsing history at the top of the dropdown list that I am trying to delete but I can't delete them. Somehow my MacBookPro (running HighSierra 10.13.3) thought it was Friday Jan 4 2041 for a day, and I looked a small number of websites. Now when I click on 'history' in the Safari Menu bar, the dropdown menu always starts with that day's browsing history. When I 'show all history', select those entries, and try to delete them, nothing happens. I can't find any combination of keystrokes that gets rid of them. But other history entries can be deleted as normal. Has anyone else had this problem and found a solution? Thanks.
MacBook Pro with Retina display, macOS High Sierra (10.13.3)