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 13 times