Microsoft SDK for Java

Q234457 HOWTO: Downgrade the Microsoft virtual machine

The information in this article applies to:

SUMMARY

Downgrading the Microsoft virtual machine is not a recommended procedure and should be done only as a last resort. Furthermore, this article should be passed to a customer only when all other options have been exhausted.

Important   This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information about how to do this, view the Restoring the Registry Help topic in Regedit.exe or the Restoring a Registry Key Help topic in Regedt32.exe.

Warning   Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the Changing Keys and Values Help topic in Registry Editor (Regedit.exe) or the Add and Delete Information in the Registry and Edit Registry Data Help topics in Regedt32.exe.

Note   You should back up the registry before you edit it. If you are running Microsoft® Windows NT®, you should also update your Emergency Repair Disk (ERD).

MORE INFORMATION

This downgrade procedure works in most cases but is not 100 percent guaranteed. Please use this at your own risk:

  1. Refer to the following article in the Microsoft Knowledge Base, which contains a list of the files installed on a system as part of the Microsoft VM installation.

    Q163637 INFO: Availability of Current Build of Microsoft VM.

  2. Unregister Msjava.dll using Regsvr32.exe. Use the following command lines:

    cd \%Windir%\system32

    regsvr32 /u msjava.dll

  3. Rename any DLL that was installed with the newer Microsoft VM. These files are listed in Q163637 after the following sentence:

    The latest Microsoft VM released under Internet Explorer is version [nnnn] and consists of the following files for the X86 platform:

    Note   Make sure that each DLL being renamed has a version number that is higher than that of the Microsoft VM you will be downgrading to. Also, if you can't rename one or more of the DLLs, you will need to reboot your computer.

    Note   Please be aware that an error made using RegEdit can render a computer unusable.

  4. In RegEdit, remove the following keys:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Code Store Database\Global Namespace\Java Packages

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Java VM

  5. On the hard disk, remove the %Windir%\java directory. Among other things, this removes all Java packages installed on the machine, including the system classes.

  6. The current Microsoft VM should now be completely removed.

  7. You can now run the version of Msjavx86.exe with a version number that matches the Microsoft VM you wish to install. You might see dialog boxes asking whether you want to replace an existing DLL with an older version that Msjavx86 is trying to install. Since these files are not part of the Microsoft VM itself, the safe answer is generally No. If you are uncertain, check Q163637.

    Important   The recent 24xx series of the Microsoft VM checks the version of Msjava.dll on the system to determine if it should install. There is a bug in the setup engine such that when there is no Msjava.dll on the system, setup reports that a newer Microsoft VM is already present. The workaround is to install the Microsoft VM with the following command line:

    msjavx86.exe /n:v

  8. Once you are confident that the correct Microsoft VM is installed and working properly, you can delete the old, renamed versions of the files.

    Important   If you normally install any custom classes on the computer, you will have to install them again.

REFERENCES

For the latest Knowledge Base articles and other support information on Microsoft® Visual J++® and the Microsoft® SDK for Java, please see the following pages on the Microsoft Technical Support site:

http://support.microsoft.com/support/visualj/ This link takes you to a site on microsoft.com

http://support.microsoft.com/support/java/ This link takes you to a site on microsoft.com

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