Hello,
Thanks for your post here.
For a clear understanding of your issue, could you please answer the following quick questions?
1. What is the exact error in the Computer Status? You may take a screenshot of the issue and send to me at v-mileli@microsoft.com.
2. Which client computers has the error status? Do all clients have the same error or just one of them?
If the Security Status shows the critical error, you may follow the steps below to check how it works:
1. Launch Windows SBS Console.
2. From the Security tab -> Security subtab, launch "View summary of virus protection for file system".
3. Will the AV report show the current status of the clients? If not (you may receive the error "The client computer WMI datastore might be corrupted "), what AV software is installed on the client?
If you have any questions or concerns, please do not hesitate to let me know.