.net 4.8 kills Server 2019

Hi,

I've been struggling with a software installation that has seen us restore several servers from backup. I've reached a point where I've replicated this problem on a completely clean installation:

- Install a new Windows Server 2019, Desktop Environment

- Apply all Windows Updates.

- Install .net 4.8 direct from Microsoft: https://dotnet.microsoft.com/download/dotnet-framework/thank-you/net48-web-installer

The server is now completely broken. Server Manager wont start. Several random services won't start. Event Viewer doesn't open.

There's a Microsoft thread here where two people reported this issue a month ago:

https://techcommunity.microsoft.com/t5/windows-server-for-it-pro/windows-server-2019-and-net-4-8/m-p/2660319

And a Reddit thread: https://www.reddit.com/r/sysadmin/comments/ps1tni/net_48_seems_to_have_broken_server_2019/

I'm somewhat floored by this problem. If things are broken as we're seeing, I'd expect a lot more noise, so I really don't know where to go with this. I'm opening a Microsoft support case right now, but I based on recent cases it'll be a few weeks before a response.

Any advise appreciated.

After many many hours of research on this I've gotten to the bottom of this. The issue is this TLS 1.2 enforcement script:

https://docs.microsoft.com/en-us/azure/active-directory/hybrid/reference-connect-tls-enforcement#powershell-script-to-enable-tls-12

Only a few days ago this script was different - it wasn't wrapped in that "if" statement. You can see the commit here: 

https://github.com/MicrosoftDocs/azure-docs/commit/e2110e5c7c59359b4ffbcb120bcfa9e736f7d7c7#diff-fe074957cf8e301b788a062c973bc4248318e58492057dff730f1f86f2718f3e

The problem is this line:

New-Item 'HKLM:\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319' -Force | Out-Null

Which creates that path (if it doesn't exist). If it does exist (which it does by default on Server 2019) it empties it.

You'd think they'd write some code to check if that registry key already exists first, and only run New-Item if it doesn't. The -Force option is clearly a problem as well -- it will overwrite what is already there.

Just experienced this problem on ONE of our three DC's. (start of march 2022)
Took me several days to find this post, which turned out to be the exact same problem.
I have to assume, since your posts are from september 2021 describing the error as being only there for a few days before Microsoft fixed it; that Microsoft made the same error once again.

I was unable to reinstall .net as it was already installed.

But I could run REPAIR using the /uninstall switch on the installer.

 - However, this problem did not get fixed, as the installer ONLY recreates the latest version regkey.

 - That means that any program dependent on an earlier version of .net, cannot run.

I was unable to run "Programs and Features" under APPS, as it is, as you may have guessed, dependent on a very early version of .net.

Now, Microsoft COULD make it much easier to fix this problem by letting the REPAIR function of the .net installer recreate ALL previous versions worth of redirects in the registry, not just the newest version.

Also, a catchall for problems pertaining to programs dependent on older versions; if a program is dependent on an older version and the registry has no knowledge (see missing .reg below), run a check if a newer .net is incorrectly installed (look for other clues to its existence). If so, then ask to run a repair on .net, don't just try a new download.

To fix the problem, I had to manually import regkeys copied from my workstation.

Instant fix. Could start programs after that, but did restart the DC anyway, just to make sure all dependencies would start up.

---

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319]
"AspNetEnforceViewStateMac"=dword:00000001
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.0]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.0,Profile=Client]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.0.1]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.0.1,Profile=Client]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.0.2]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.0.2,Profile=Client]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.0.3]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.0.3,Profile=Client]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.5]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.5.1]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.5.2]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.5.3]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.6]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.6.1]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.6.2]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.7]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.7.1]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.7.2]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.8]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\Client]
[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Microsoft\.NETFramework\v4.0.30319\SKUs\Default]

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319]
"AspNetEnforceViewStateMac"=dword:00000001
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.0]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.0,Profile=Client]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.0.1]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.0.1,Profile=Client]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.0.2]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.0.2,Profile=Client]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.0.3]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.0.3,Profile=Client]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.5]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.5.1]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.5.2]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.5.3]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.6]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.6.1]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.6.2]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.7]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.7.1]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.7.2]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\.NETFramework,Version=v4.8]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\Client]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\v4.0.30319\SKUs\Default]

---

Hope this helps any other poor soul who stumbles onto this post.

Well heck ... who was to know that I was the next luck person to run into this issue on 2 different servers on 2 different domains. Darn lucky the tech from INFOR found this posting and we were able to recreate the registry keys!

I am still looking for what triggered the issue, so no updates were pushed out that I can tell. 

Thank you all for this! I found the correct registry keys in another server and was able to export them and import into the broken servers. I am also still trying to figure out how the keys were removed. Any info there would be great!