Right, so today I realised I am running out of storage space. I decided to then move some of my apps onto my SD card, it took about 10 minutes to move the 4 apps that I wanted and then I decided to uninstall some of the less used ones. While I was doing that, my phone randomly switched off and once it turned itself back on, it has been stuck on the screen with the message ' Android is starting... Optimising app 2 of 4 (SD Card) '. I know these things take take however, I do not think it should take 4 hours. I am using a HTC One M8 and I believe I am on adroid 6 Marshmallow. I cannot do anything else apart from waking the screen up.