Before you encounter a problem, you do not see Microsoft Excel application in the Windows Server R2 system, "Component Services", "DCOM", and reinstalling Office is still a problem.
Reason:
In the x64 environment of Windows Server R2, there is no control over DCOM that is executed in x32, which means that MMC runs in x64 mode, and it is unable to manage DCOM running in x32 mode.
If you open Excel, you can see that Excel is running in 32-bit mode
Open Component Services directly from Control Panel when MMC is running in 64-bit mode, it excludes DCOM running in 32 mode.
So if you need to run MMC in 32-bit mode, you can see Microsoft Excel application
In addition, I also encountered another problem:
If the operating system is Windows Server 2012 (not R2), running MMC in 32-bit mode still does not see Microsoft Excel application, and this issue is not resolved.
Problems with Microsoft Excel application cannot be seen on 64-bit systems