After I talked with a few colleagues I find out that an application installed on all computers in the company blocks the updates, the app in question is bitglass.
I stopped it's service and removed the associated script in Settigns->Proxy. Some updates (windows defender) were installed, but updates for version 1809 failed to install.
sfc/scannow showed some errors in the logs which I couldn't fix with dism. At this point SFCFix started to crash and was unusable.
dism couldn't fix the issue because the ISO created with MediaCreationTool was newer than what it was installed and couldn't find the files at that version, they were newer in the ISO.
On some forums it was suggested to install .NET Framework 3.5, I did that using dism and the ISO created. Still no luck with sfc and dism.
After I rebooted the machine I stopped the bitglass service and removed the script in proxy. Today, while browsing the net, a message popped up and notified me that I have an update ready to install, this time it was a newer Windows version (1903). The files were downloaded, at reboot hanged. Stopped the computer from button and on power up the installation starts. A few reboots later and Windows starts.
Run sfc and found something, but it was repairable.
Now, I'm going to create an ISO with MediaCreationTool to have the exact same version available in case some files we'll be corrupted again.
