An alarm light will flash on the display to advise you that the dust container is full. Your Synthesis cleaner compacts the dirt, so the container will not require emptying as often as a conventional vacuum cleaner. However it's still good to check and empty the container especially if it has been taken off the product to clean the pre motor filter.
Dust container full indicator
To remove the dust container for emptying start by pressing the release catch at the back of the product. Then take the container to your dustbin and press the catch to release the dust flap and allow the contents to empty into your dustbin. Give it a shake to ensure that all the dirt has emptied out. Also remove any debris tangled around the plunger. Once it has been emptied, press the pin lid shut and refit the container onto the product.
press the release catch to open the flap, make sure the plunger in the centre of the picture is clean and free from any debris