Grammer Error in HS3

I keep getting the below error in my log.

Aug-15 00:00:14 Error Exception during grammar generation, loading grammar: The process cannot access the file 'C:\Program Files (x86)\HomeSeer HS3\Grammar\Grammar_Data_HS#Default.hs' because it is being used by another process.

Any clue to what is causing the error or how to fix?

Thanks.