Cannnot Active Outlook claasic Apps

Question

There is an issue that requires expert assistance. Our company is using the Entra ID P1 plan, along with the following services and subscriptions:

• Exchange Online (Plan 1)
• Microsoft 365 Business Basic
• Microsoft 365 Business Premium
• Microsoft 365 Copilot
• Microsoft Defender for Endpoint P2
• OneDrive for Business (Plan 2)

Recently, while setting up a colleague's computer, I signed in with the company's Microsoft account when officially activating Windows 11 and synced the account with Entra ID.

Then, after completing the installation of Microsoft 365 and opening Outlook (Classic), I encountered the following error: "Failed to register a VB Script dll. Reinstall or run Regsvr32.exe Vbscript.dll to self register."

According to past reports, this error often occurs due to a mismatch between the Microsoft Office language settings and the system's preferred language settings. However, I have already verified that the preferred language matches the system language during setup, yet the issue still persists.

Later, I opened Regedit.exe and attempted to locate the registry key at the following path:

Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Setup

I compared the registry keys with those on a computer where Outlook (Classic) was working properly and made the following changes:

• Added RegisterForms as a REG_DWORD and assigned it the same value as UpdateProfiles (REG_DWORD).

As a result, I was able to successfully open Outlook (Classic) and receive emails. However, when opening each email, I encountered another error: "Failed to install a custom action."

Finally, I once again compared the registry keys on the problematic computer with those on a computer where Outlook (Classic) was working properly. I noticed that a key seemed to be missing:

"OlkLicensingFeatures REG_BINARY"

I suspect this might be related to licensing. However, after logging into our Microsoft Admin Center and Intune to check, I couldn’t find any missing or incorrectly configured options.

Since this issue remains unresolved and I have not been able to get expert assistance from the community, I am hoping to receive support from a Microsoft expert here.