Boot issue after SSD upgrade

[Longhorn6120]

Hi all. This is my first post here so apologies if it's in the wrong section. Also, if I'm overlooking some newbie protocols maybe someone could give me a heads up there too.

A few years ago I upgraded my wife's 2009 MacBook with an SSD and all went well. My own 2009/2010 iMac 27" has recently developed an erratic hard drive and was reporting some errors and failings so I decided to upgrade to an SSD over Christmas. I put in a 2TB Crucial MX500 SSD and now it flies like the wind - it's never been so fast and feels like a new machine - but it now has an unusual delay at boot up.

Where it used to go straight to the grey Apple logo with the progress bar underneath as soon as I powered up it now hangs on a white screen for approximately 45 secs before the Apple logo appears. Total boot-up time is around 1-1/2 minutes (pre-upgrade boot-up time was over 5 minutes so a huge improvement), but around half of that time is that plain white screen that never used to be there. It'd be great if I can stop that happening, especially as I never had this problem when I upgraded my wife's MacBook.

Any idea what's causing this and how to fix it?

Many thanks in advance.

 

[Thessman]

Check if you have selected your new disk as the default startup disk in system prefs.

 

[Longhorn6120]

Perfect, thanks! I don't remember doing that on the MacBook, but I guess I must have.

Boot-up time is now 25secs to the login screen, then approx 5-10 secs more to fully boot up once the password has been input. Can't see a 13yo Windows device achieving that!

Thanks again, very helpful.

 

[unrigestered]

Can't see a 13yo Windows device achieving that!

might be...
my 12.something years old Win 7 laptop has completely finished booting from hitting the power button to the Windows desktop in 20s though

and i didn't even optimize anything on that, but i hear they even improved boot times with Win 8. i think some people got it to boot within 8s or so at that time.
Not sure how long Win 10 would take on it though. and it's too old to even qualify for a legit Win 11 installation.