Este foi o meu problema do dia... Esta postagem vai ser ingles, preciso praticar!!!
The Reporting Services Windows Service could no be startet after applying the SQL Server 2008 R2 SP2.
There were no messages at all under the Application log, and all the system log stated was:
Timeout (30000 milliseconds) waiting for the SQL Server Reporting Services (Grumpy) service to connect.
I tried changing the account that SSRS was running under, but it would
still not restart, and I was considering remove SP2.
I could not find any error from SSRS, so I tried changing the service startup timeout
value to 60 seconds.