Hi, I am writing an multithreaded Excel Add-in program and an error. I
currently have no clue how to solve this. Please help. The description is as
below:

I created an Excel Add-in in C#. The add-in contains a separate thread that
read and write to the worksheet constantly.

I got a COMException when the program is accessing to the cell while I
clicking on the worksheet.

HRESULT of the exception is: 0x800AC472

I could mitigate this problem by having the add-in to retry after this
exception occur. However, Excel will not exit cleanly after exception occur.
That is, the Excel process still running after my add-in have been shutted
down and Excel window closed. I have to kill the process manually :(

Anyone having the same problem?