maina33 Said:
"when I got the support.apple.com/ipad/restore I used cable to connect to device to computer but there is still blank screen"
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A. Single Out this Cable:
Try using a different cable. If it works, then it is an issue with the cable. If no, then it is likely an true with the connection (i.e. port on the Mac)
B. Boot in Safe Mode:
In Safe Mode, Login Items do not run at login, certain preferences are set aside, and damaged system files (i.e. caches) are then reset. So, once booted in to Safe Mode, wait 30 seconds, and then boot up normally, attempting another update install. Go Here: How to Use Safe Mode on your Mac - Apple Support
C. Try a New Admin User:
What happens when you create a new administrator user, and log into it? Do you still get this error? If not, then it is likely an error with the current user. If so, then it is likely an error with your Mac.
D. Reset your SMC and your NVRAM:
(Applies to Intel-Basel Macs Only) Sometimes changes (i.e. Installations) are made to the system and then settings (i.e. Networking) become corrupted, technically. So, reset both on your Mac. So, reset the SMC and reset the NVRAM or PRAM. It might take three tries. to fix this. So, be certain you have the time to do so.
Start With This: