Stop the EPM Suite service on the application server
Open EPMControl.exe from the Corporater installation folder
Right-click "Workspace & Data" and choose "Re-index"
A new window will open showing the process of the re-index
When the re-index process is completed, start the EPM Suite service
Note that the startup might take a bit longer than usual due to the re-building of the index on the disk.
Startup is complete when there is a green arrow on both the "Server" and "Workspace & Data" tabs in EPM Control Center