Vista （包括其他Windows版本），硬盘的系统恢复还原功能可能用掉了非常多的空间。如果你硬盘空间不够了，你可以查一下。
在我家的一个机子150G的C盘上，就用了36G。如果仔细查，可以用TreeSize Professional软件（强烈推荐这款软件）发现“System Volume Information”目录用了36G，且不能打开看。
但是大家可以用Windows 的vssadmin命令行来控制或释放:
1) 查一下用掉多少空间：
C://>vssadmin list shadowstorage
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2005 Microsoft Corp.
Shadow Copy Storage association
For volume: (C:)////?//Volume{96bdb307-7b54-11dc-b7c8-806e6f6e6963}//
Shadow Copy Storage volume: (C:)////?//Volume{96bdb307-7b54-11dc-b7c8-806e6f6e69
63}//
Used Shadow Copy Storage space: 36.946 GB
Allocated Shadow Copy Storage space: 38.404 GB
Maximum Shadow Copy Storage space: 33.695 GB
2) 查一下resize参数，用最后一条例句该为你认为合适的大小：
C://>vssadmin resize shadowstorage
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2005 Microsoft Corp.
Error: A required option is missing.
Resize ShadowStorage /For=ForVolumeSpec /On=OnVolumeSpec [/MaxSize=MaxSizeSpec]
- Resizes the maximum size for a shadow copy storage association between
ForVolumeSpec and OnVolumeSpec. Resizing the storage association may
cause shadow copies to disappear. If MaxSizeSpec is not
specified, there no limit to the amount of space it may use. As certain
shadow copies are deleted, the shadow copy storage space will then
shrink. MaxSizeSpec must be 300MB or greater and accepts the following
suffixes: KB, MB, GB, TB, PB and EB. Also, B, K, M, G, T, P, and E are
acceptable suffixes. If a suffix is not supplied, MaxSizeSpec is in
bytes.
Example Usage: vssadmin Resize ShadowStorage /For=C: /On=D: /MaxSize=900MB
3）我改为还原空间上限5G
C://>vssadmin Resize ShadowStorage /For=C: /On=C: /MaxSize=5120MB
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2005 Microsoft Corp.
Successfully resized the shadow copy storage association
C://Downloads>vssadmin list shadowstorage
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2005 Microsoft Corp.
Shadow Copy Storage association
For volume: (C:)////?//Volume{96bdb307-7b54-11dc-b7c8-806e6f6e6963}//
Shadow Copy Storage volume: (C:)////?//Volume{96bdb307-7b54-11dc-b7c8-806e6f6e69
63}//
Used Shadow Copy Storage space: 0 B
Allocated Shadow Copy Storage space: 0 B
Maximum Shadow Copy Storage space: 5 GB
申明：普通用户慎用，请查阅相关指令说明了解实际功能用途
我的主网页：http://vincentyang.cn/blogs/vincentyang/archive/2009/10/09/windows.aspx