Boot up: no entry followed by Apple logo but no progress bar...
I have had this issue after a week or so since updating to Catalina 10.15.4. I don't know if it is connected.
I have to reset NVRAM {CMD+SHIFT+P+R} upon reboot every time to get the progress bar and boot successfully now. I have tried pulling my plug out for 15 secs (from my iMac, not myself!) and restarting with no success either.
I also repaired all drives on Disk Utilities.
Set start up drive in Recovery mode too.
I have had it could be internal battery probs, but nothing solid on that...
Any ideas anyone (I know the issue has been raised before with no solutions)
It is rather annoying and needs a fix from apple really!
Many thanks for any help!
iMac 27" 5K, 10.15