I ran a full scan with windows Defender yesterday, have just booted up & have a greyed out windows defender symbol in my notification area . I open it & am told 'you have not run a scan for 15 days' .Not the first time this has happened . advice pls

Hi, barrythegreek and welcome to Bleepingcomputer,
Try running the scan again and see what happens...try disable and reenable it again that often works. Had a similar promblem but it was the updates that was wrong. Try that and reply back.