MS CRM SQL Server CPU Utilization shows 100% - Troubleshooting steps

We had a weird issue with MS CRM SQL server recently where the CPU utilization of sql server constantly shows 100% for a long time. When we checked in the task manager we found that sql process alone is taking around 98 - 99%. We have application and database on different servers. We tried to reboot both the servers couple of time and the behavior is such a way that the utilization goes down whenever we restart the machine and raises up to 100% after 10-15 min.

But the only relief from our side is the CRM application is not entirely down but the performance was less.So, we got some time to debug into the issue.

We tried the following steps in our process of troubleshooting the issue:

1. First thing to check if there are any recent changes or deployments made to the system.
2. In the task manager check the process that is consuming the cpu utilization.
3. Check the application logs and system logs in EventViewer of the crm server. If the app server and sql servers are hosted in different servers then check the event logs in both the servers.
4. Stop the Asynchronous Service in MS CRM server and check the cpu utilization. If it gets down then issue is probably with the ms crm app server. It could be due to customizations you made which is running into deadlock situations.
5. If it is still showing 100% then stop the sql server services and check the utilization.
6. Start the CRM AsyncService and see the utilization.If it works fine, then start the sql services as well.
7. If you still find the issue, you can Start Running the SQL Profiler to see if any query is taking long time to execute. If you find any, then disable the functionality that is making use of that query for a while and check the utilization.
8. Check if any event log appears in System. Check if automatic windows updates are turned ON on the server. Sometimes windows updates might not run successfully and causes the issue so check the last updated time from windows and see if the error in the event log starts occurring from that time. It will  be set when the windows updates run for the next time or you can manually run the windows updates and restart the server.

 The reason in my case is the automatic window updates failed to run successfully that impacted the sql server process.

If the above steps did not resolve your issue and if you are making use of some third party services running on the same server then, instead of restarting the services, try stopping the services one at a time, check if there is any impact on the utilization and once you are done with stopping all the services and start the services one at a time. This way you can get closer to the root cause of the issue. 

Hope this saves sometime in your debugging process!!