Trouble booting Pi3ModelB from SD card

Hello, I have a Pi3 Model B and have downloaded and flashed the OSMC img to an SD card (Cat 10). I have tried flashing with both Etcher and Popsicle and in either case I just get a black screen and no signal from my HDMI output suggesting it isn’t booting. I’ve tried with 2 different SD cards. I have downloaded the image twice also.

The Red light is on so I know I have power (this was a functioning RetroPie half an hour ago so I know the device works). The green light flashes 4 times and then stays lit and then repeats (4 flashes then hold).

Any ideas/suggestions? Thanks.

OK, I had to pull the HDMI cable out as well as the power then re-insert HDMI and then power. Bizarre.

Sorted now.