I was getting this error after upgrading my system from Windows 2008 standard to Windows 2008 R2
[Window Title]
Visual Studio Just-In-Time Debugger
[Main Instruction]
An unhandled exception ('System.IO.FileNotFoundException') occurred in OWSTIMER.EXE [3492].
The Just-In-Time debugger was launched without necessary security permissions. To debug this process, the Just-In-Time debugger must be run as an Administrator. Would you like to debug this process?
[V] View process details [Yes, debug OWSTIMER.EXE] [No, cancel debugging]
[Expanded Information]
Process Name: OWSTIMER.EXE
User Name: NETWORK SERVICE
Could not load file or assembly 'Microsoft.IdentityModel ...........
try this
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=eb9c345f-e830-40b8-a5fe-ae7a864c4d76&displaylang=en
