Do you by any chance have a backup image of your drive? If not, unfortunately it is time to start installing drivers and software from scratch:( I absolutely recommend using something like acronis true image to back up your system drive once you have everything installed. I couldn't count the number of times this has saved me. Only takes about 10 mins to restore all of your system to its previous perfect state, no matter what happens.

crackle and pops are almost always due to audio driver / buffer settings.
 
something that probably easily could have been adjusted.
(I say easily in a general type of way)

Thanks Tenfoot - of course I didn't create a backup image! That would have been sensible! I'll take your advice in future though!

chuckebaby, I tried some outrageous settings - mega long latency - and still crackles, fizzing, glitches...

Chuck is absolutely right. Once you have your software re installed, edit>preferences>driver settings>asio panel should be your first port of call!

Sorry - just saw your later post:) Out of synch.

Does the Mackie 400F even have Win 10 drivers?

"Does the Mackie 400F even have Win 10 drivers?"
Very Important as JonD is saying first thing to see in an upgrade are audio drivers compatability.
Peace

Win 10 driver - not specifically. But win 7 driver worked in 8, and I used asio4all at one point with great success.

I'm really fed up... :(

Asio4all is a band aid at best, it just tries to fool Sonar into thinking it's a proper Asio driver when it's not.

I might give up recording and turn to fishing.

The weirdest thing was that uvi player wouldn't even start! Bias amp crackled, certain synths worked standalone in 64bit, others in 32 bit. Strange.