no safe mode?

[ISKOTB]

I just updated to the final 10.12.4..I try holding either or shift keys as I'm booting but I still can't get to safe mode?

Thanks

 

[Gregg2]

holding either or shift keys as I'm booting

???

Holding down the Shift key as it boots is what you want to do.
Check this out:
https://www.cnet.com/news/what-to-do-when-a-mac-wont-boot-to-safe-mode/
(I just did a quick search online. Google or Yahoo! is your friend.)