WiX C# Custom action not working when MSI started from Add Remove Programs

[radu-solomon-dnsf]

WiX Version: 5.0.1
.NET Framework: 4.8.0
OS: Windows 11 x64

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I have a very strange issue and can't for the life of me track it down. We have a WiX based MSI installer that we run. When the MSI is run in Modify mode and the user selects the Remove option they are shown a UI asking them for a PIN to perform the removal.

I have my property, CA and Button all wired up but here is the strange part it works most flows except one.

• If i run the MSI via cmd prompt using msiexec /i package, click Remove, input the pin - CA works and returns valid or invalid

• If i run the MSI via appwiz.cpl, click Remove, input the pin - CA works and returns valid or invalid

• If i start the modify via the new Add Remove programs, click Remove, input the pin - CA throws error 2896 and my installer ends

The only difference i can see in the MSI logs for the runs:

• case when run from cmd prompt - MsiTrueAdminUser = 1 shows up / Calling process: C:\Windows\system32\msiexec.exe
• case when run from , appwiz.cpl - RestrictedUserControl = 1 shows up / Calling process: C:\Windows\explorer.exe
• case when run from AR Programs - RestrictedUserControl = 1 shows up / Calling process: C:\Windows\ImmersiveControlPanel\SystemSettings.exe

I tried to elevate the CA, generate more logs, etc i can't see what it happens and why it throws that error on the CA. As far as i can see it doesn't even start to execute it at all it just errors out but i could be wrong

All the CA does now for testing is this

[CustomAction]
public static ActionResult IsValidUninstallPinUi(Session session)
{
    var upin = session["UPIN"];
    session["VALIDUPIN"] = upin.IsNotEmpty() && upin.Equals("123456") ? "1" : "0";
    return ActionResult.Success;
}

And the way its linked to the button

<Property Id="VALIDUPIN"
		  Value="0"
		  Secure="yes" />
<CustomAction Id="ValidateUninstallPinUi"
			  DllEntry="IsValidUninstallPinUi"
			  BinaryRef="InstallerActionsBinary"
			  Impersonate="no" />

Output when run from cmd prompt

Action 14:29:13: AgentMaintenanceDlg. Dialog created
MSI (c) (2C:38) [14:29:18:786]: PROPERTY CHANGE: Adding WixUI_InstallMode property. Its value is 'Remove'.
Action 14:29:18: AgentUninstallDlg. Dialog created
MSI (c) (2C:38) [14:29:23:014]: PROPERTY CHANGE: Adding UPIN property. Its value is '123'.
MSI (c) (2C:38) [14:29:23:165]: Doing action: ValidateUninstallPinUi
MSI (c) (2C:38) [14:29:23:165]: Note: 1: 2205 2:  3: ActionText 
Action 14:29:23: ValidateUninstallPinUi. 
Action start 14:29:23: ValidateUninstallPinUi.
MSI (c) (2C:38) [14:29:23:196]: Creating MSIHANDLE (1) of type 790542 for thread 8248
MSI (c) (2C:B8) [14:29:23:196]: Invoking remote custom action. DLL: C:\Users\abc\AppData\Local\Temp\MSI8AC0.tmp, Entrypoint: IsValidUninstallPinUi
MSI (c) (2C:E4) [14:29:23:212]: Cloaking enabled.
MSI (c) (2C:E4) [14:29:23:212]: Attempting to enable all disabled privileges before calling Install on Server
MSI (c) (2C:E4) [14:29:23:212]: Connected to service for CA interface.
MSI (c) (2C!54) [14:29:23:509]: Creating MSIHANDLE (2) of type 790531 for thread 4948
MSI (c) (2C!54) [14:29:23:509]: Closing MSIHANDLE (2) of type 790531 for thread 4948
MSI (c) (2C!54) [14:29:23:571]: Creating MSIHANDLE (3) of type 790531 for thread 4948
MSI (c) (2C!54) [14:29:23:571]: Closing MSIHANDLE (3) of type 790531 for thread 4948
MSI (c) (2C!54) [14:29:23:760]: Creating MSIHANDLE (4) of type 790531 for thread 4948
MSI (c) (2C!54) [14:29:23:774]: Closing MSIHANDLE (4) of type 790531 for thread 4948
MSI (c) (2C:B8) [14:29:23:884]: Closing MSIHANDLE (1) of type 790542 for thread 8248
Action ended 14:29:23: ValidateUninstallPinUi. Return value 1.

Output when run from AddRemovePrograms

Action 13:46:57: AgentMaintenanceDlg. Dialog created
MSI (c) (5C:C4) [13:46:58:921]: PROPERTY CHANGE: Adding WixUI_InstallMode property. Its value is 'Remove'.
Action 13:46:58: AgentUninstallDlg. Dialog created
MSI (c) (5C:C4) [13:47:03:055]: PROPERTY CHANGE: Adding UPIN property. Its value is '123'.
MSI (c) (5C:C4) [13:47:03:142]: Doing action: ValidateUninstallPinUi
MSI (c) (5C:C4) [13:47:03:142]: Note: 1: 2205 2:  3: ActionText 
Action 13:47:03: ValidateUninstallPinUi. 
Action start 13:47:03: ValidateUninstallPinUi.
MSI (c) (5C:8C) [13:47:03:175]: Invoking remote custom action. DLL: C:\Users\abc\AppData\Local\Temp\MSIC8B1.tmp, Entrypoint: IsValidUninstallPinUi
MSI (c) (5C:CC) [13:47:03:175]: Cloaking enabled.
MSI (c) (5C:CC) [13:47:03:190]: Attempting to enable all disabled privileges before calling Install on Server
MSI (c) (5C:CC) [13:47:03:190]: Connected to service for CA interface.
Action ended 13:47:04: ValidateUninstallPinUi. Return value 3.
MSI (c) (5C:C4) [13:47:04:124]: Note: 1: 2205 2:  3: Error 
MSI (c) (5C:C4) [13:47:04:124]: Note: 1: 2228 2:  3: Error 4: SELECT `Message` FROM `Error` WHERE `Error` = 2896 
DEBUG: Error 2896:  Executing action ValidateUninstallPinUi failed.
The installer has encountered an unexpected error installing this package. This may indicate a problem with this package. The error code is 2896. The arguments are: ValidateUninstallPinUi, , 
Action ended 13:47:04: MaintenanceWelcomeDlg. Return value 3.
MSI (c) (5C:A8) [13:47:04:124]: Doing action: FatalError