ＶＳＳ出现Um.dat may be corrupt 错误的解决

  
SYMPTOMS
When you try to start Visual SourceSafe, you may receive the following error message:
Um.dat may be corrupt
CAUSE
New Database
When you create a new database, a 3.1 database format is converted to a 5.0 database format, which is then converted to a 6.0 database format. If the conversion is not completed, the database may still be in 3.1 format. Check the Version.dat file to see if the version number is 6.0. If the version number is 5.0, the database is still in 3.1 format.
Existing Database
Alternatively, this problem can occur with an existing database. In this scenario, the Um.dat file may be corrupted.
RESOLUTION
New Database
To resolve this problem, manually run the Ddconv.exe file against the database to convert the database format. Alternatively, you can run the Ddupd.exe file if you want to upgrade the database to 6.0 format.

For example, go to the VSS\Win32 folder in a command prompt window, and then type one of the following commands: • ddconv path to data directory
• ddupd path to data directory

Existing Database
To resolve this problem, build a new Um.dat file. Note that when you build a new Um.dat file, you must add all of the users again.

To build a new Um.dat file, follow these steps: 1. Create a temporary folder named C:\Sstemp.
2. Click Start, click Run, type cmd, and then click OK.
3. Go to the VSS\Win32 folder in the command prompt window, and then type the following command:
mkss c:\sstemp
4. In the VSS\Win32 folder at the command prompt, type the following command:
ddconv c:\sstemp
5. In the VSS\Win32 folder at the command prompt, type the following command:
ddupd c:\sstemp
6. Copy the Um.dat file from the C:\SStemp\Data folder to the Visual SourceSafe data directory.
7. Rename the Rights.dat file in the Visual SourceSafe data directory as Rights2.dat.
8. At a command prompt, run the analyze -f command against the database.
9. Add all of the Visual SourceSafe users again.
10. Reassign rights to the Visual SourceSafe users.

STATUS
This behavior is by design.