Described is a revert preview mechanism, which gives the user a chance to temporarily remount a storage volume with the contents of a shadow copy, and then evaluate the computer system as if reverted, including allowing full I/O read and write operations to the storage volume. A temporary storage location is provided to cache data writes. Read requests are read back from the temporary storage location if the corresponding volume location has been written, or are read back from the shadow copy of the volume if not written since the revert preview operation began. In the case of a revert preview of the boot volume, an API is used to specify a correct shadow copy instance of the system registry hive, which needs to be loaded following reboot, but before the shadow copy driver is loaded. Use of the API loads the correct instance on the next reboot.