A Windows 2003 or Windows 2008 system may not boot up when the system hive of the registry becomes too large. The exact size of the system hive that causes this problem depends on the configuration of the system. Repeatedly adding and deleting volumes or disk devices will increase the size of the system hive. For example, performing many off-host backups may add and delete many volumes and increase the size of the system hive. The increase in size of the system hive can be seen in the growth of the system file %SystemRoot%\system32\config\system.  

Running the VxScrub utility as a part of regular system maintenance will shrink the registry size and avoid this problem. Rebooting the system after running vxscrub is mandatory. With the -p option, the utility can uninstall and clean up unused volume, disk, and MountManager registry entries. It also purges the registry to physically shrink the size of the registry. Run vxscrub -p from the command line and then immediately reboot the system to perform this operation.  

Instructions for installing the files:  
1. Click the Download Now link below to begin the file download
2. Copy this file to a temporary location and then double click on the file to begin the extraction process
3. Choose a location to extract the files and click Extract
4. After all files have been extracted,  click OK on the "All files have been extracted" notification prompt
5. Review the Readme.txt file provided with the download for specific installation instructions

VxScrub usage overview:  

USAGE-1:
Vxscrub [<-a|-b|-l|-v>] [-d] [-m] [-q] [-c]  
Uninstall/cleanup Volumes/Disks/MountManager entries that are no-longer present and free up the registry entries used by them.  
 

-a  Uninstall ALL unused volumes  
 

-b  Uninstall all unused BASIC volumes  
 

-l  Uninstall all unused LDM volumes  
 

-v  Uninstall all unused VERITAS VM volumes  
 

-d  Uninstall all unused disk instances  
 

-m Cleanup MountedDevices database  
 

-q  Quiet mode. No output on screen  
 

-c  Just check. Do not actually uninstall/cleanup.    
 

Note: Registry [System hive] will not physically shrink in this mode. Consider USAGE-2 or USAGE-3 to actually shrink the registry.

USAGE-2:
Vxscrub -p [-q]  
 

-p  Perform -a -d -m above and also purge the registry [system hive]  
 

-q  Quiet mode. Do not show uninstalled/deleted entries.  
 

Note: You have to REBOOT following a successful purge.

USAGE-3:
Vxscrub -forcepurge [-c]  
 

-forcepurge  Purge the registry [system hive] to shrink its size  
 

-c Just check and report the new size. Do not actually purge.
 

Note: You have to REBOOT following a successful purge.