ISSUE:
The RTM installer of Office Web Apps will also create a folder on the C drive called “OneNoteMerge” when installing to another drive. The folder is not created on the specified non C drive path. This is one root cause of the unhealthy status and some event log errors.
FIX:
This has been fixed in the most recent version of the installer that is slipstreamed with SP1
WORKAROUND:
To correct the issue on an Office Web Apps server that was installed with the RTM installer you can perform the following steps:
1. Stop the Office Web Apps service (stop-service wacsm)
2. Move the following folder and all of its contents from the C drive to the correct installation path you specified. (C:\Program Files\Microsoft Office Web Apps\OneNoteMerge)
3. Start the Office Web Apps service (start-service wacsm)
4. The health status should now show healthy and errors for the OneNoteMerge ping check should no longer appear
NOTE:
We do not recommend installing on a non system drive if you are using VMWare, unless you perform a VMWare workaround
(Source)
