There are various numeric limits, imposed either in the OS or in the specific shadow copy provider. Here is a table that summarizes all the numbers.

 

Note that the limit below is per volume, not per system.

 

Maximum number of shadow copies per volume

Windows XP

Windows Server 2003

Provider

Shadow type

The in-box provider

(ships with Windows)

Writers, non-persistent (used for backup)

1

512

 

No writers, non-persistent

n/a

 

Writers, persistent

No writers, persistent

Shadow Copies for Shared Folders

(no writers, non-persistent)

64

Third-party Hardware providers

 

Writers, non-persistent (used for backup)

n/a

 

Provider-specific (No max limit imposed by VSS)

No writers, non-persistent

Writers, persistent

No writers, persistent

Shadow Copies for Shared Folders

n/a