Use Guidscan.exe to View or Change GUID in a VSS Database

ID: Q176780

The information in this article applies to:

Microsoft Visual SourceSafe, 32-bit, for Windows versions 4.0a, 5.0, 6.0

SUMMARY

The GuidScan.exe utility allows you to see the value of the GUID within a Visual SourceSafe database by reading the um.dat file. You can also generate a new GUID and replace the contents within the Visual SourceSafe database. The Visual SourceSafe utilities Ssarc.exe and Ssrestor.exe use the GUID stored in the um.dat file to determine if an archive is being restored to the same database or a different one. Some administrators have built new Visual SourceSafe databases by copying the contents of the data directory to a new location and then deleting all the files and projects. A problem can occur if other projects and files are added to the new database, and then you attempt to restore an archive from the original database to the new one. Since the GUIDs are the same in both databases, SSRESTOR does not attempt to rename the file and project logs it is restoring, and it can overwrite existing files and projects in the new database.

This utility can be used to compare the GUIDs in different databases and create a new GUID if needed without having to recreate the um.dat and rights.dat, which would force the administrator to re-add users and project rights.

MORE INFORMATION

The following files are available for download from the Microsoft Download Center. Click the file names below to download the files:

GuidScan.exe

For more information about how to download files from the Microsoft Download Center, please visit the Download Center at the following Web address

http://www.microsoft.com/downloads/search.asp

and then click How to use the Microsoft Download Center.

Contents of ReadMe.txt

ReadUm.exe is a 32-bit, Console application that can read the structure of the um.dat file in a Visual SourceSafe database. This file contains user information such as User names and passwords in tokenized form. While most of the information in the FORMAT, RECORD HEADER and UM HEADER sections of the um.dat file are of no interest to users, the presence of a GUID within the um.dat indicates the database is in 5.0 format. It could also indicate that files have been archived or restored from a database that was originally in 4.0 format using the 5.0 utilities Ssarc.exe or Ssrestor.exe.

ReadUm will return the following entries from these sections of the um.dat file:


   FORMAT: Signature:[ ] Version:[ ]
   RECORD HEADER: Size:[ ] Type:[ ] Checksum:[ ]
   UM HEADER: Entries:[ ] Users:[ ] GUID Set:[ ]

If GUID Set is a non-zero value, a GUID Value will also be displayed. You will then be asked if you want to create and replace the existing GUID with a new one. Clicking Yes will generate a new GUID and replace the existing GUID in um.dat.

Be very careful if you replace the GUID. The archive and restore utilities SSARC and SSRESTOR that come with Visual SourceSafe 5.0 depend on the GUID to determine whether an archive file is being restored to the same or a different database. Replacing the GUID after archiving files may cause the files not to be able to be restored correctly to the same database. For this reason, please backup the existing um.dat and rights.dat before replacing the GUID.

Additional query words:

Keywords : kbfile kbSSafe400 kbSSafe500 kbSSafe600
Version : WINDOWS:4.0a,5.0,6.0
Platform : WINDOWS
Issue type :