During these time period we faced below errors when we was trying to browse eventviewer
MMC has detected an error in a snap-in and will unload it
This problem occurred on Windows 2008 R2 server
MS Article https://support.microsoft.com/en-us/help/4508640/event-viewer-may-close-or-you-may-receive-an-error-when-using-custom-v suggest hotfix KB4503277 (Preview of Monthly Rollup for Windows 7 SP1 and Windows Server 2008 R2 SP1)
Futhermore was released newer hotfix versions:
2019-07 Security Monthly Quality Rollup for Windows Server 2008 R2 for x64-based Systems (KB4507449)
