Can't start CMO--error, please help me

[BigBog]

It is different from mine. Yours is more up-to-date. Mine is 4.8.9214.0

So it was updated recently and that may be the cause?

Yes, It appears that it was updated--and if I remember correctly Windows did an update--
I am on the "extended Win 10 plan" until later in 2027--an extra year because my machine was not "Win 11 ready"/ungradable--for whatever reason.

I hate those Updates. btw, they always break something---lol

[Nikel]

The update should appear in Settings...Windows Update...View Update History...Quality updates

[BigBog]

Latest Update for .NET was:

.NET 8.0.33 Security Update for x64 Client on 10/26/2026

Also;

2026-KB5128925 Cumulative Update for .NET Framework 3.5, 4.8 and 4.8.1 for Windows 10 Version 22H2 on 10/13/2026

.NET 8.0.32 Security Update for x64 Client on 10/15/2026

[Dimitris]

Can you open a Powershell (not normal command-prompt) window and type and run this:

$t = New-Object System.Data.DataTable
[void]$t.Columns.Add("Table",[string])
$r = $t.NewRow()
$r["Table"] = "x"
$t.Rows.Add($r)
"OK: " + $t.Rows.Count
[System.Data.DataTable].Assembly.Location
[System.Data.ForeignKeyConstraint].Assembly.Location

And tell us what it returns. Thanks.

[BigBog]

Hi,
It didn't like this line (5):

$t.Rows.Add($r)

"You cannot call a method on a null-valued expression"
"At line: 1 char:1" ( all in red)

I did not enter the last three lines.

[BigBog]

Update--I typed it wrong--see attached--

[BigBog]

I ran the last three lines anyway--

[Dimitris]

Right, this confirms that there is something fundamentally broken in your OS environment, rather than a fault in the application.

Next, please run this also in Powershell:

Get-HotFix | Sort-Object InstalledOn -Descending | Select-Object -First 15
(Get-Item C:\Windows\Microsoft.NET\assembly\GAC_64\System.Data\v4.0_4.0.0.0__b77a5c561934e089\System.Data.dll).VersionInfo.FileVersion
(Get-Item C:\Windows\Microsoft.NET\assembly\GAC_32\System.Data\v4.0_4.0.0.0__b77a5c561934e089\System.Data.dll).VersionInfo.FileVersion
(Get-Item C:\Windows\Microsoft.NET\Framework64\v4.0.30319\System.Data.dll).VersionInfo.FileVersion
(Get-ItemProperty "HKLM:\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full").Release

[Nikel]

BigBog, you may copy and paste the whole block that posted Dimitris.

This is what I get from the first one, running PowerShell as Administrator.

PS.png (29.38 KiB) Viewed 476 times

[BigBog]

Hello guys,
Here is the results from running the requested test (attached)--

[Dimitris]

Okay.

Now, in a normal cmd window, please run this:

set COMPLUS_ZapDisable=1
powershell

And then, in the Powershell prompt, run this again:

$t = New-Object System.Data.DataTable
[void]$t.Columns.Add("Table",[string])
$r = $t.NewRow()
$r["Table"] = "x"
$t.Rows.Add($r)
"OK: " + $t.Rows.Count
[System.Data.DataTable].Assembly.Location
[System.Data.ForeignKeyConstraint].Assembly.Location

[BigBog]

OK---I think were getting closer--lol (see attached)

[Dimitris]

Okay, give Command a try now.

[BigBog]

I had to reinstall the new version---I had been playing the 32bitLegacy version, so will be a few minutes--

Hopeful----

[BigBog]

Well---progress--maybe?---different error message (attached).
I really thought for a second it was fixed because it took longer to pop up--

[Nikel]

Post the new exceptionlog and DxDiag files.

Something in the event viewer?

[BigBog]

Hi,
Here are the files--
Where is the Event Viewer?

[Nikel]

The event viewer is part of Windows.

1. Press the Windows key or click Start.
2. Type Event Viewer into the search bar.
3. Click Event Viewer.

Why don’t you try again the new build Dimitris posted, 1900.23a?

https://forums.matrixgames.com/viewtopi ... 7#p5297337


dxwnd could cause problems to CMO?


Though it seems still a .NET problem, this is another of its libraries.

Diagnostics
---------------

Windows Error Reporting:
+++ WER0 +++:
Fault bucket 1460255301405954324, type 4
Event Name: APPCRASH
Response: Not available
Cab Id: 0

Problem signature:
P1: Command.exe
P2: 1.0.0.0
P3: 6ac842f7
P4: clr.dll
P5: 4.8.9363.0
P6: 6ac7ff21
P7: c0000005
P8: 0000000000058ca8
P9:
P10:

[BigBog]

Hi,
I've checked my .NET and rebuilt it--no joy.
I've tried a bunch of suggestions from GPT Chat as well as from you guys--but no joy.
I may have to wait to run this until I get another rig--

Thanks!
BigBog

[Nikel]

I am not saying that you do it, but what would happen if you uninstall this update.

2026-KB5128925 Cumulative Update for .NET Framework 3.5, 4.8 and 4.8.1 for Windows 10 Version 22H2 on 10/13/2026

Would .NET go back to a previous version without this incompatibility with CMO?