iMac Pro Slow Boot - FileVault?


macrumors newbie
Original poster
Nov 13, 2018
I picked up a refurbished iMac Pro recently. I set it up and have FileVault running. I noticed when it starts up it takes a very long time (40 seconds +) after I hit the login screen (the one with the icons) before the Bluetooth mouse connects. The loading also feels a little glitchy and the keyboard takes a few additional seconds longer to connect. If I disable FileVault this delay doesn’t occur. Is this normal behavior with FileVault running?

Here’s a video of it happening:



macrumors 6502
Sep 3, 2010
This is normal. It is due to the new T2 chip and two-stage boot process IMHO (the bridgeOS has to boot and verify the macOS before the later can boot). A disappointing regression, but not that critical I think unless you reboot all the times.

A few months back I captured this video which shows my iMac Pro booting next to my original Macintosh from 1984. Guess which one boots faster:



macrumors 601
Aug 6, 2007
I don't have that input mouse delay, but I have all sorts of problems with mine and that t2 chip. (slow startup and long shutdown sometimes and occasional startup kernel panics that just power off entirely) I now have disabled all the Secure Boot utility stuff in the recovery environment as well as file vault and anything else t2 is in charge of. Watch for startup or other kernel panic reports to do with "bridge os". There are still obviously issues that haven't been fixed since this first cropped up in January.

I hate the T2 chip!!

update: seems to have settled down for the most part. only happens occasionally now although all the secure stuff still turned off which may otherwise affect things.
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macrumors member
Oct 8, 2008
I also reflected how slow the boot up time is on my Imac Pro. 35-45 seconds.

But it was the same with the Mac Mini 2018. T2 chip related perhaps? I do not use Filevault.