I have now tried to upgrade from Windows 7 Ultimate, 32 bit, to Windows 10 ten times and experienced ten failures. Each time the error messages are the same, for both the blue screen and on the Windows Update window.
On the blue screen I see "The PC has experienced a problem, please wait we are collecting information: System Thread Exception Not Handled." Collecting information? Whose collecting information? And where's it going? I'd like to see that information. (a few sarcastic questions I have)
The error message on the Windows Update page is as follows: Windows update experienced an unknown error, c1900101-30018.
As I normally do when I encounter a problem, I surf the web looking for solutions for the specific information I have. Namely the two error messages above. And I must say it is quite heart felt to see all the definitive solutions to my problem, as long I go along with the poster who said, "that didn't work for me." And let me apologize now for any sarcastic statements I will no doubt make. Nothing I'm about to relate has fix the UNKNOWN problem which Windows Update is encountering.
I did say I search for solutions when encountering problems, and I did that the first time the upgrade failed. One post said to run "chkdsk" and "sfc /scannow" which I did. No problems were found. One post said to go into Windows -> Software distribution -> Download and delete the contents. Which I did, still no help. I even ran several suggested Microsoft Fixit and Troubling shooting programs. Again, nothing fix the UNKNOWN error.
I've tried tweak after tweak but nothing cured the UNKNOWN error problem. As a side thought, while doing all this, I decided I better backup my hard drive only to find "Backup and Restore" were no longer working; I also had to buy a larger portable external drive to hold my HD contents--bought a Seagate 2TB portable expansion external drive. So, now I had another problem to research and try to find an answer. The possible answer can in a post which suggested running MiniToolKit, which I did. After running the program I noticed the system was running rather sluggish, and decided to reboot. Once the task bar appeared I noticed an icon on the Action Center icon which I hadn't seen before. Imagine my surprise after opening the Action Center to find my system was being backed up. That was one thing fixed, I think.
On to more posts, another suggesting Windows Updater--I believe it was called, which installed a program HotFix (I think). Anyway, this didn't fix anything either. Emeisoft Emergency Kit was suggested in another post, which I tried. It's a maleware program which ended up finding three PUPs which weren't hurting anything but I got rid of them anyway. More posts, more suggestions, none of which were use to me or I'd already tried.
Then another post caught my eye for Tweaking.com Window Repair, something I hadn't tried. Ran it, followed the directions, the program found some problems, let it fix those problems, thought now my system could be upgraded to Windows 10, ran the upgrade, and received the same to error messages I mentioned at the beginning of this post. Sooo...before the 10th attempt at upgrading to Windows 10, and something I did several times before, I disabled both Avast and Malwarebytes, Windows Defender, and Windows Firewall. I also disconnected the printer, USB 2.0 hub, the new drive I bought, and started the upgrade. And for the 10th time windows upgrade failed. It is nice, I must say, after each fail my system was restored to it's chipper self. Thank goodness.
Needless to say I'm at a loss what to do to find this UNKNOWN error. Trying this or that hasn't worked, so more of the same isn't a solution. Somewhere, someone must have the information which was gathered when the blue screen appeared. Information which might tell what the error is and maybe provide a clue how to fix it. Unless someone has any more ideas how to sleuth out this UNKNOWN error, it looks like I'm living with Windows 7 Ultimate 32 bit.