If your hook and loop sanding discs are no longer sticking to your sander this is likely due to the worn out hooks on your sander’s back-up pad. The back-up pad on your sander has hooks which receive and hold the loop backing of your sandpaper discs to keep it in place. Over time, these hooks heat up during constant sanding and begin to soften and melt, reducing their ability to grab and hold the sanding discs. Eventually, these hooks will become worn out to the point where they will no longer grab hold of your sanding discs, and this is when you may notice they fly or fall off the sander when in use.
One option would be to replace the sander’s entire back-up pad. However, a cheaper and easier option is to simply replace the hook portion of your sander’s back-up pad. To read about how to do this see the following: Applying Hook and Loop Converter
You can shop our hook and loop converter here: Hook & Loop Converter