I run Windows Update manually, so it doesn't decide to kick off on its own while I'm doing something critical. Like downloading a sample library or watching The Walking Dead.
 
This morning I noticed I hadn't run it since August, and there were like a hundred security updates in the queue. So I kicked off the updates and the first thing that popped up was "Downloading Windows 10". Yikes! I wasn't ready for that, so I quickly clicked the "Stop download" button. 
 
Later in the day, I had to reboot. I went to make a cup of coffee and when I came back, it said "Ready to install Windows 10". Ah, crap. Oh well, what the hell, I understand it's easy to roll back. So I told it to go ahead.
 
Still waiting for the install to complete, so I don't yet know if this is about to turn into a bad day or what. At least now it'll finally stop pestering me about upgrading. So there's that.

Should be fine Dave, but you may have to reinstall some things....

Lets hope all goes well. Dave it should go well. I do hope you like it. 

My upgrade, running the first preview, was flawless, and I was astonished...
and everything still worked...making it even more impressive to me...

After having beta tested every version of Windows since 3.1, it was quite 
a welcome experience....LOL

Fingers crossed...I'm assuming that most things that worked under 8.1 will be OK with Win10 as well.
 
SONAR shouldn't be a problem, and Focusrite says my interface will work (as long as I have the right Firewire card, which I think I do).
 
The other biggie is my VirtualBox VM, which should be alright. Lots of people have been runing Win 10 within the VM since beta, so the VM itself should be OK. 
 
Hmm, wouldn't it be great if my Tranzport started working again? Just dreaming.

On my test computer i was able to get my old delta card working by installing the driver in compatibility mode.

Perhaps that would work for your tranzport.

If worse comes to worse just do a restore.
 
I've had a few ghosts in the machine because of that last major update last week.
It change my dual boot sequence & placed a new partition file on one of my internal hardrives.
Because of that I had to re-register a few plugins. Other than that it seems to working fine.
 

Everything worked for me except ilok software, but let's be honest if you look at ilok the wrong way it could stop working. After re-registering everything was fine.

ilok came up fine for me but Omnishpere2/Trillian/Stylus RMX need a reauthorization
 

My pc and Sonar are actually running better after the November Windows 10 update.
I used to get daily, random audio engine drop-outs. These have not occurred for 3 days (and counting) now since the update.