微软近日发布了一个修复补丁，帮助用户解决Windows 7和Windows 7 SP1中存在的一个启动缓慢的问题。微软证实，如果用户在计算机中创建了太多的系统还原点，那么在启动系统时会发现速度非常慢。
在知识库文章KB2555428中微软提供了修复该问题的补丁，并且阐述了导致这一问题产生的原因。每个还原点都会创建一个Windows快照，而 Volsnap.sys在系统启动进程中必须要进行验证。当你创建了太多的还原点，ReadyBoot功能的引导就可能会超过512KB的限制，从而导致启动I/O操作无法预缓存，因此启动过程就会非常慢。
Consider the following scenario:
You have a large hard disk installed a computer that is running Windows 7.
You create many restore points on the computer.
You try to start the computer.
In this scenario, the startup process may be very slow.
This issue occurs because the boot plan for the ReadyBoot feature exceeds the size limit of 512 kilobytes (KB). Each restore point creates a snapshot of Windows that Volsnap.sys must validate during the startup process. When you create many restore points, the boot plan for the ReadyBoot feature eventually exceeds the size limit of 512 KB, and cannot be stored. Therefore, startup I/O operations are not precached, and the startup process is slow.
Note The boot plan is stored in the following registry entry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\rdyboost\Parameters\
BootPlan
KB2555428补丁申请地址：
