Why does. after descaling. does my yellow light stay on and NOT go green?

Honestly, no idea, but you might look up it user's manual

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0CCUQFjAB&url=https%3A%2F%2Fwww.dolce-gusto.es%2Fmanuals%2Fdownload%2Fdownload%2F%3Fd%3D0%26file%3Dcustom%252Fupload%252FFile-1413310872.pdf&ei=JL1bVbjrJa-BsQS474HwCw&usg=AFQjCNFvkYiWHVxSxnnf_YCrxm2CO1i3ig&sig2=1tQMrxDNo0LVBQGx2VmE1Q&bvm=bv.93756505,d.cWc&cad=rja

KINDLY DO DESCALING BUT IF YOU DO YOU HAVE PRESS THE POWER BOTTOM FOR 5 SECONDS AND IT WILL BLINK YELLOW OR ORENGE ONLY THEN YOU CAN DO DESCALEING THE LIGHT WILL GO BACK TO GREEN BUT ONLY AFTER DESCALING

Batteries are getting low..change the batteries.

Read your manual more closely. You also need to activate the hot water tap in accordance with the descaling instructions.

I have the same problem with my Delonghi Magnifica, so maybe there is a glitch in the machine..

Try doing another rinse cycle until water tank empties. I had to do that a couple of times, then the red exclamation mark came on. Then I turned knob to off position, refilled water tank, pressed the descale button for 6 seconds, green light came back on and it did its priming.

Removing the red descaling light is simple.
1. Fill reservoir with half vinegar and half water (no need for the special descaling product from Tassimo).
2. Turn on machine.
3. Insert yellow cleaning disc found in back of machine.
4. This is where most people have the their problem...You must hold the start button for 3 to 5 seconds for the descaling program to start. Both green and red light will flash.
5. Once started, use a large cup to catch the output of water.
6. The machine will cycle through the descaling program in about 30 to 45 minutes. Be paitent!!!
7. Once completed, run many cups of plain water through the system to remove the vinegar taste.
8. Red light problem is solved.

Hope this works for you.

Solution: Just refill the water tank with water (no descaling solution) all the way to the "Max Line". Then run the full descaling program again --takes approx. 20 minutes. After the program runs completely you will get the yellow "standby" light on and the red "descaling" light will be off.

Next time you descale, be sure and fill your water tank to the "Max Line" before running the descaling program.
Hint: An incomplete cycle (not full tank) is what makes the red light stay on. In other words, it's staying red to tell you to run a full cycle (beginning with the water tank filled to the "Max Line"). Hope this tip is helpful!

Solution: Just refill the water tank with water (no descaling solution) all the way to the "Max Line". Then run the full descaling program again --takes approx. 20 minutes. After the program runs completely you will get the yellow "standby" light on and the red "descaling" light will be off.

Next time you descale, be sure and fill your water tank to the "Max Line" before running the descaling program.
Hint: An incomplete cycle (not full tank) is what makes the red light stay on. In other words, it's staying red to tell you to run a full cycle (beginning with the water tank filled to the "Max Line"). Hope this tip is helpful!