Clock and weather disappeared from top panel. Can't restore them

I just started using Mate on my Raspberry Pi2. Today I noticed all the notifications (clock, weather etc) have disappeared from my top panel. I got a message on-screen saying Ubuntu Mate has experienced a problem related to the panel. I tried to add everything back using [right click][add to panel] but that doesn’t work. Can anyone help? Is this a known issue?

You can always restart the panel if one of the applets crashed. You can press ALT+F2 (for run dialog) or CTRL+ALT+T (for terminal) and type this command:

mate-panel --replace

Unfortunately, without knowing what happened leading up to the error, I can't confirm if this is a known problem.

If you need to completely reset your panels back to the default, open MATE Tweak and choose a different layout. If you can't access the menu, open the Run Dialog (ALT+F2) or Terminal (CTRL+ALT+T) and type this to open it:

mate-tweak

Thanks for the response. Nothing seemed to work. All the applets except "Applications, Places, System & Firefox failed on both top and bottom panels. The only way I was able to fix it was by reloading the RPi2 image onto the MicroSD card and starting again. Since I don’t know what triggered the failure I can’t provide any further feedback, but I will be watching to see whether it happens again.