A method in a computer system for guaranteeing execution of a content image, wherein the content image is a software program that is to be executed on the computer system, the method comprising: under the control of an update client executing on the computer system, obtaining the content image and its associated content image policy for execution of the content image on the computer system, the content image policy containing properties of the corresponding content image comprising an approximate execution time for the content image, and an obey service window policy flag, the obey service window policy flag indicating whether a service window policy is to be applied to the corresponding content image; when the service window policy is to be applied to the execution of the content image, determining whether a service window is available for executing the content image by comparing a present time, a start time and an end time of the service window, and the approximate execution time for the content image, the service window specifying a time window with the start time and the end time, and wherein the service window is available when the present time is within the time window, and when a length of time from the present time to the end time is sufficient for the content image to execute; and upon determining that the service window is available, executing the content image on the computer system during the available service window; when the service window policy is not to be applied to the execution of the content image, executing the content image on the computer system. under the control of an update client executing on the computer system, obtaining the content image and its associated content image policy for execution of the content image on the computer system, the content image policy containing properties of the corresponding content image comprising an approximate execution time for the content image, and an obey service window policy flag, the obey service window policy flag indicating whether a service window policy is to be applied to the corresponding content image; when the service window policy is to be applied to the execution of the content image, determining whether a service window is available for executing the content image by comparing a present time, a start time and an end time of the service window, and the approximate execution time for the content image, the service window specifying a time window with the start time and the end time, and wherein the service window is available when the present time is within the time window, and when a length of time from the present time to the end time is sufficient for the content image to execute; and upon determining that the service window is available, executing the content image on the computer system during the available service window; when the service window policy is not to be applied to the execution of the content image, executing the content image on the computer system. obtaining the content image and its associated content image policy for execution of the content image on the computer system, the content image policy containing properties of the corresponding content image comprising an approximate execution time for the content image, and an obey service window policy flag, the obey service window policy flag indicating whether a service window policy is to be applied to the corresponding content image; when the service window policy is to be applied to the execution of the content image, determining whether a service window is available for executing the content image by comparing a present time, a start time and an end time of the service window, and the approximate execution time for the content image, the service window specifying a time window with the start time and the end time, and wherein the service window is available when the present time is within the time window, and when a length of time from the present time to the end time is sufficient for the content image to execute; and upon determining that the service window is available, executing the content image on the computer system during the available service window; determining whether a service window is available for executing the content image by comparing a present time, a start time and an end time of the service window, and the approximate execution time for the content image, the service window specifying a time window with the start time and the end time, and wherein the service window is available when the present time is within the time window, and when a length of time from the present time to the end time is sufficient for the content image to execute; and upon determining that the service window is available, executing the content image on the computer system during the available service window; when the service window policy is not to be applied to the execution of the content image, executing the content image on the computer system. executing the content image on the computer system.