Reduce the size of your System Volume Information folder by shrinking the shadow storage.

Use vssadmin list shadowstorage to list the current Shadow Copy Storage size.

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{278ce142-19d8-11e1-9176-806e6f6e6963}\
Shadow Copy Storage volume: (C:)\\?\Volume{278ce142-19d8-11e1-9176-806e6f6e69
63}\
Used Shadow Copy Storage space: 15.681 GB (39%)
Allocated Shadow Copy Storage space: 16.152 GB (40%)
Maximum Shadow Copy Storage space: UNBOUNDED (100%)

In the example above there is no limit set on Maxium storage. To set a limit use the maxsize= command. In Windows Server 2008+ this can be set as a percentage of disk space.

C:\>vssadmin resize shadowstorage /on=C: /For=C: /Maxsize=4GB
vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool
(C) Copyright 2001-2005 Microsoft Corp.

Successfully resized the shadow copy storage association

After setting maxsize rerun list shadowstorage to verify/review the updated configuration.

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{278ce142-19d8-11e1-9176-806e6f6e6963}\
Shadow Copy Storage volume: (C:)\\?\Volume{278ce142-19d8-11e1-9176-806e6f6e6963}\
Used Shadow Copy Storage space: 2.81 GB (7%)
Allocated Shadow Copy Storage space: 3.279 GB (8%)
Maximum Shadow Copy Storage space: 4 GB (10%)