Went to download Sierra, app store shows that it is downloaded, started to install and had to cancel and now it will not let me install. Have tried to restart and nothing is working. Any help would be wonderful
MacBook Air (11-inch Mid 2012)
Well, I found a solution for Sierra and High Sierra.
You need a pen drive or external drive to install or new Mac OS X won't install (anymore).
MAKE BACKUP OF YOUR DATA BEFORE PROCEED!
1. Download Sierra or High Sierra from AppStore;
2. Follow this: Create a bootable installer for macOS - Apple Support
3. Use Alt/Option when reboot your Mac and choose the Pen Drive or external drive
4. At this point (YOU WILL LOSE ALL YOUR DATA, MAKE BACKUP BEFORE PROCEED), if you haven't, I suggest you to create 2 partitions on your HD drive, one for data and another to MAC OS. Run Disk Utility and format your HD with HFS journaled (if you have SSD on your system, you can format with APFS)
5. Run Install Mac OS Sierra or High Sierra.
Works like a charm for me!
I wrote up a possible solution here:
https://mostlydev.com/macos-sierra-setup-will-not-start/
It's a workaround that turns the dmg installer into a pkg. Started up just fine after that!
Downloaded Sierra but won't install.
