Any how , thank you for sharing  your experience so far -
giving a lot of helpful  infos about the firewire card , DAW aso.
Hope that your helpfulness will get paid back.
 
Pragi
 

Thinking of, maybe, reformatting my audio drive to see if that might cure the "Device Not Migrated" issue. (Because, basically I'm running out of things to try) I am assuming the drive should be formatted in NTFS, not Fat 32? Is that correct. 

FWIW i had this problem/message when using my Boss GT100 multi pedal with W10 creators update in April

Tonelab (the software you use to alter the settings on the unit) would not rcognise or shake hands with the hardware. I’m using W10 prof. However on my laptop, running W10 Home, the unit worked perfectly, with the same update. Go figure ...... !

So, what fixed the issue for me, is you need to go into Privacy settings and make sure the mic options are turned ON. Then reboot. Creators edition, for whatever reason, defaults it OFF for some people. If you google you’ll find you’re not alone with this message.

This may (or may not) help you !

Cheers,
Jerry

Rod, 
have you tried to put the firewire card into another pci-e slot?
Sure you already tried to enable/disable the onboard sound chip, or ?
 
regards

So, at this point, I have tried everything I can and here's where I am....
Everything "works" but, whenever I press Play, I get the spinning blue disk with about a one second hesitation before play actually starts. When I set up a loop, the first time through, at the end of the loop, it stops play and hesitates (with the spinning blue disk) for about one second. After that first time through, the loop plays fine.
This is the same behavior I had on my old computer (which is what led me to getting a new computer).
The constants between my old computer and the new computer are Cakewalk by BandLab and, my firewire card, which I transferred from my old computer to my new one. (NOTE: The firewire card is a Siig unit with a TI chipset) 
All my issues started about six months ago on my old computer. It was over six years old and I just assumed it was the culprit, that's why I got this new computer.
Unless anybody has any better ideas, I guess I will have to buy a new firewire card and see if it makes any difference.
Oh, also, Studio One works just fine on both computers. No lag, no hesitation, works perfectly. I just REALLY prefer Cakewalk to Studio One.

If the problem appeared at a certain time, one thing to try is an uninstall of CbB and clean install of the last known working version (or older) of Platinum. My guess is the problem will still be there. If it is, this points to a driver, OS and/or hardware issue.

scook - This is so frustrating. I even went so far as to buy a new computer to try to resolve this issue. Yes, I do believe this all started right near the end of Platinum (I have lost track since it's been going on so long).
This being a new computer, everything is, obviously, a fresh install.
The driver for the Focusrite Saffire Pro 40 is still the same version as before. As I said, I transferred my old firewire card. (I wanted to buy a new one but, my Wife said I had already spent too much$$ Ha ha!!) I guess my next thing is to buy the new firewire card and see if that fixes things.
 

If Studio One works fine, it is not your interface. Don't waste money on a new one just to troubleshoot.

I forget if you had tried doing a global FX bypass (E) for troubleshooting? It seems you have eliminated disk/audio buffer possibilities, but you may have a plugin with lookahead doing something.

One other note, I had to back out Saffire MixControl to 3.4 when I went to Win10, but that issue was present with everything.

Hmmmm, failure to migrate, slow data transfer from disc to memory,, this kind of reads like......… You may quite possibly be experiencing the first stages of mechanical hard drive failure with your audio drive.... (?)
 
You did mention transfer these problems over from your older system.
 
And you should also experience a very noticeable increase in speed and power from a 6 year old i5 to a current tech i7.
 
 

rodreb
It just dawned on me.... I replaced a 6 year old i5 with 8 gb RAM with a new i7 with 16 gb RAM and can basically see no difference in performance. Just doesn't seem right. 

The RAM most likely has NOTHING to do with it. I've done 100+ track Sonar projects and have never had one that uses more than 2GB. Secondly, a 6 year old i5 is not that much slower than a new i7; it's gonna be more power efficient, but only modestly faster.
 
To me, it sounds like what's happening is that the wait you're experiencing is Sonar cueing up all the audio files to start playback. Depending on how many take-lanes there are per track, it could be way more than even the number f tracks you're trying to play, which brings me to the most important thing here:
 
You upgraded your CPU but you're using spinning hard drives and not SSDs! That's a terrible way to go, your old i5 with a pair of SSDs would blow the pants off your new system. Especially if there's fragmentation on the HDD, having to cue up many different WAV files would take 10 times as long as on an SSD.
 
In the least, you should try adding an SSD as a project drive and running the projects from there. Ideally you want one as a system drive too.
 
R