startup disc

Hello, I have been getting the gray question mark when I start my MacBook Pro (A1502 with 3.1GHz, i7). I've figured out how to navigate to the OS X utilities page. However, the HD isn't showing up and so there is nothing to try and fix the startup disk on/reinstall my OS High Sierra on. From...

Hi, when apple upgraded HFS+ to APFS, macOS startup disk was not showing on windows 10 bootcamp Control Panel. this last until recently when a bootcamp Control Panel on windows 10 pops up an update. I have applied this update on iMac and MBP. macOS startup disk is now showing on "windows 10...

SO im able to boot and get to the login screen, but the loading bar sits at 3/4 lead and then does nothing. Ive left it for hours and it sits there, and then sometimes it goes to an all blue screen with vertical black lines then restarts, any thoughts? I attached a picture of the specs!

My trusty laptop finally died and I bought a mid 2017 imac which is running high sierra. My problem is that much of my software won't run on high sierra and I would like to either use the HD from the laptop (which has el capitan on it) as a start up disc or make a time machine back up of it and...