it is because the database where is doing the fragmentation has "_" on its name like DB_Data, how to solve this ??

same for me, just here it is not working sql 2008 express version. I dont understand why ?

Hi Sue, yes it is showing a Windows account user, I have seen this before. So I suppose is setup correct..??

I tried with execute as Owner still the same error.

proxy account was created long time ago from someone else , so I am not sure if this is created correctly,...

no we don't use encryption