# Release Notes for Virtual PC

## How to Use These Notes

Back to Top

These notes contain important information that was not available when the documentation for Microsoft® Virtual PC 2004 was written. You can find more information on the Web site listed at the end of this document.

## Preinstallation Information

Back to Top

### Before you begin an upgrade or new installation

Before you install Virtual PC, we recommend that you take some precautionary steps to identify or eliminate potential problems. In particular, we recommend that you:

- Back up your current files.
- Stop any tasks or jobs that are using network resources. The installation process temporarily disrupts existing network connections while network drivers are installed. Although network connections are automatically re-established when the installation finishes, the disruption can cause network-based tasks to fail.

## Virtual Machine Additions

Back to Top

### You might need to manually uninstall some versions of the Virtual Machine Additions feature

You must manually uninstall the following versions of Virtual Machine Additions before you can use the virtual hard disk with the current version of Virtual PC:

- Any version of Virtual Machine Additions for OS/2.
- Versions of Virtual Machine Additions that were included with Virtual PC 4 or earlier.

Manually uninstall Virtual Machine Additions using the same version of Virtual PC that was used to install it. An existing virtual hard disk may be unusable if you attempt to run it using Virtual PC 2004 and it contains one of the versions of Virtual Machine Additions that is listed above.

Note that the version of Virtual Machine Additions that was included with Virtual PC 5 (except Virtual Machine Additions for OS/2) does not need to be manually uninstalled. You will be prompted to upgrade this feature when you start the virtual machine.

### Earlier versions of Virtual Machine Additions cause errors on certain operating systems

Errors occur when you start certain operating systems that have an earlier version of Virtual Machine Additions installed. Known errors and the recommended solutions are as follows:

- When starting Windows® Millennium Edition, Windows 98, or Windows 95 for the first time on a virtual hard disk created with Virtual PC 5.2, you will see a blue screen with a message that FSHARE cannot load because it is out of date. Press ENTER to continue, and then upgrade Virtual Machine Additions to the current version.
- When starting Windows 95 (retail) for the first time on a virtual hard disk created with Virtual PC 5.2, you will see an error message that vpchelp.exe performed an illegal operation. Upgrade Virtual Machine Additions to the current version to resolve the problem.
- When starting Windows XP for the first time after upgrading to Virtual PC 2004 Virtual Machine Additions on a virtual hard disk that was created with Virtual PC 5.2, you will see an error message that the Virtual PC Services Application encountered a problem and needed to close. Restart the operating system to resolve the problem.

### Error messages are displayed on the first startup of Windows Millennium Edition guest operating systems after Virtual Machine Additions is installed

The first time a Windows Millennium Edition guest operating system is started after Virtual Machine Additions is installed, you will see two error messages about msiexec.exe. Click OK to close the error message. These error messages do not affect the functionality of the virtual machine.

### Guest operating systems on which Windows Millennium Edition is installed must be manually restarted after installing Virtual Machine Additions

Virtual PC 2004 installs Windows Installer 2.0, which updates the version of Windows Installer that is included with Windows Millennium Edition. For the update to Windows Installer to be complete, Windows Millennium Edition must be manually restarted.

## MYVIRTUALMACHINES Environment Variable

Back to Top

### MYVIRTUALMACHINES environment variable controls the default location where new Virtual Machine Configuration (.vmc) files are created

By default, Virtual PC creates the virtual machine configuration files (.vmc) in My Documents\My Virtual Machines. Virtual PC then stores other files that are used by the virtual machine in the same folder as the .vmc file. This is controlled on the host operating system by the MYVIRTUALMACINES environment variable. You can change the MYVIRTUALMACHINES environment variable to a different location. For more information on how to change environment variables, consult the documentation included with the version of Windows on which you have installed Virtual PC 2004.

## Additional Resources

Back to Top

For more information about Virtual PC, see the Microsoft Web site.(http://www.microsoft.com/virtualpc)

## Copyright

Back to Top

Information in this document, including URL and other Internet Web site references, is subject to change without notice. Unless otherwise noted, the example companies, organizations, products, domain names, e-mail addresses, logos, people, places, and events depicted herein are fictitious, and no association with any real company, organization, product, domain name, e-mail address, logo, person, place, or event is intended or should be inferred. Complying with all applicable copyright laws is the responsibility of the user. Without limiting the rights under copyright, no part of this document may be reproduced, stored in or introduced into a retrieval system, or transmitted in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise), or for any purpose, without the express written permission of Microsoft Corporation.

Microsoft may have patents, patent applications, trademarks, copyrights, or other intellectual property rights covering subject matter in this document. Except as expressly provided in any written license agreement from Microsoft, the furnishing of this document does not give you any license to these patents, trademarks, copyrights, or other intellectual property.

© 2003 Microsoft Corporation. All rights reserved.

Microsoft, MS-DOS, Windows, and Windows Server are either registered trademarks or trademarks of Microsoft Corporation in the United States and/or other countries.

The names of actual companies and products mentioned herein may be the trademarks of their respective owners.