When you are installing SharePoint 2010 Service Pack 1 (SP1), you might encounter the following error multiple times during the installation.
An unhandled exception (‘System.Security.Cryptography.CryptographicException’) occurred in OWSTIMER.EXE .
This has been known to occur just because you have Visual Studio 2010 installed. You’ve probably seen it in the past with day-to-day operation of your SharePoint environment. I encountered this issue before and it has never seemed to prove to be an issue. Just click the No button and let the installer finish. You have nothing to worry about (yet) and your upgrade should proceed just fine. It will likely pop up multiple times throughout the installation process.