The message filter indicated that the application is busy

When I try to read content of word doc by oWordDoc.Content, It throws exception:

The message filter indicated that the application is busy. (Exception from HRESULT: 0x8001010A (RPC_E_SERVERCALL_RETRYLATER))

I tried OApplication.Visible = false, It also did not work.

I think there is another instance of msword already working on background, maybe invisible and displaying some message box nobody will click on. Try to kill that instance by task manager, then try to ensure you are closing msword when you use it in automation.