MS pulled this update. 

fireberd
V1809, Build 17763.1 has been pulled by MS.  No specific reason but the problem some are having with deleted files may be one reason.  I've had 17763.1 for over a week as I get the advanced "Insider" versions and didn't have problems with it either.  Not sure of what circumstance(s) cause the problems.  
 
But, I'll repeat the suggestion (really should be mandatory) to make a full drive (all partitions) image backup to a separate drive BEFORE doing any major update such as this.  The free (and most popular on computer forums I visit) Macrium Reflect or some other imaging program should be used to make the disc image.  DO NOT use the built in Windows backup as its incomplete and does not do a full backup.
 
Macrium Reflect free:
 https://www.macrium.com/reflectfree

Thanks, as usual, for your helpful advice. I'm going to do this Macrium thing soon (I've already bought a large external HD) and try to get back in the game. I thought by going offline, all would be fine and it is but, for me, it's no fun. When I mix, I like to enjoy doing it slow and taking time each day to watch groove 3 tutorials or search the forums and try to learn new things and advance my skills. Now, with no internet connection, I haven't recorded in 6 months. It's no fun, no learning, no GAS, no new plugins to try. It's like a school assignment. So instead, I write music and am in the most prolific time of my life. I use TRackS to have fun with live recordings thru a Zoom camera. But I want to begin recording by Christmas as a present to me, that means finishing a lot of old projects, then making the macrium reflection, whatever that is (I am not into tech anymore, I have terminal cancer and there is a limit to what I'm going to waste my time with), then upgrading to Pro (how will that go? As soon as I go online, Microsoft will trash my pc within minutes, guaranteed), turning off updates and then enjoy life once again. I will also try to rejuvenate my pcs killed within hours of one another by last years Fall update (both Win 7). But what about all the people out there who are just people and know nothing about pcs? They work, they play, they raise families. They know nothing about Acronis, Macrium or Clonezilla. And Microsoft kills their pcs so they have to buy a new one and Microsoft makes money. They (Microsoft) trash their pcs as a business model and pollute the environment with discarded refuge. It's disgusting to me.

Thanks to all who reported the buggy win update was removed. Here is the latest news update about it from the IT forum. Amazingly it states,
 
And, a quick glance into the Insider feedback hub, shows this to be a reported problem before. When it happened then (multiple times) it happened to a group of people who knew that beta products can have problems. They signed on for it. In this instance, Microsoft released beta software on an unsuspecting world and should pay for it.
 
Fireberd, you're an insider, did you know the release was buggy? I can't imagine you did?
 
They continue,
 
It’s time to go back to the drawing board. Microsoft’s update testing mechanisms are broken. Bill Gates once wrote about Trustworthy Computing. At the time the intended purpose was to make products more secure. By definition, the word ‘trustworthy’ means so much more than that, and its time for Microsoft’s customers to hold the company to the full extent of that definition. Customers are continually delaying updating security of products because they don’t ‘trust’ software updates coming from Redmond. This is not acceptable.
Riddle me this: How can over a million “Insiders” have tested 1809 and this issue didn’t crop up at all?
 
The whole article is here:
 
https://myitforum.com/microsoft-removes-buggy-windows-10-1809-upgrade/ 

Update that I got from a Computer Analyst friend.  One drive seems to be the key for many that have lost documents.  I was not affected as I don't use one drive.
 
I had been using the Insider version that is the same as the 1809 for about a week without problems.  There was no reason for me to assume the 1809 update was buggy.  However I don't do a lot with my PC - web surfing, MS Office 365, a couple of computer support forums and as a DAW.   
 
I have a Dell Inspiron 15 (5577 model 7th gen i5) that I use for off-site recordings.  I updated it to 1809 and nothing "broke".  Its even got less installed than my desktop. Its got Win 10 home, Sonar and studio one 3, drivers for my recording hardware and nothing else.