Recent Items Menus Have Stopped Working On My Imac


Recently I noticed that on my iMac, running El Capitan, the Open Recent menu has stopped getting updated, both in the Apple menus, and for apps, and both for the Open Recent menu item, and the list that pops up from the Dock.

I checked in System Preferences | General | Recent Items, and it is saying None. I have tried a number of times to reset it to 20, but it shows up as None when I get back in to System Preferences.

I hope someone can help me sort this problem out.

TIA Mark
Removed this:

/Users/YOURUSERNAME/Library/Preferences/, then log out and back in.