Outlook on the Desktop stopped working suddenly with COMException (0x80080005)

[Fro2n99]

Hello,

I’ve been using Outlook on the Desktop (OTD) without any issues until yesterday, but starting today the application fails to start and shows the following error:

System.Runtime.InteropServices.COMException (0x80080005): Retrieving the COM class factory for component with CLSID {0006F03A-0000-0000-C000-000000000046} failed due to the following error: 80080005 (CO_E_SERVER_EXEC_FAILURE).

Here is what I have tried so far:

Outlook itself runs normally — emails and calendar open without any problem.

No recent Windows or Office updates were installed.

Completely uninstalled Microsoft 365 (Office suite) and reinstalled it from scratch.

Completely uninstalled Outlook on the Desktop, removed all cached data from
%localappdata%\Outlook on the Desktop,
%appdata%\Outlook on the Desktop,
and deleted registry keys under
HKEY_CURRENT_USER\Software\Outlook on the Desktop.

Reinstalled the latest OTD version afterward, but the same error persists.

Ran the following Outlook repair commands:

outlook.exe /resetnavpane

outlook.exe /regserver

outlook.exe /cleanviews

Outlook and OTD are both executed under the same permission level (non-administrator).

I’m using the classic Outlook, not the new preview version (“New Outlook”).

Even after reinstalling both Microsoft 365 and OTD completely, the COM initialization error (0x80080005) still appears.

Could you please advise what might be causing this issue, or whether any recent Windows/Office component could conflict with OTD?

Please reply to me directly by email at ehdrl06@khu.ac.kr, as I would like to receive your response there.
Thank you for your help.

Best regards,
Dongki Kim