What should I do if Parallels offers to install Parallels Tools every time when I run VM?
This message appears when Windows automatically runs the Parallels Tools CD after the startup and tries to install Parallels Tools.

To solve the problem you have to disconnect the CD: start up the virtual machine, choose Devices from the Parallels Desktop menu and select CD/DVD-ROM - Disconnect. Reboot your virtual machine.

I've updated Parallels Desktop to the latest version but when I boot Windows I keep getting black screen in the guest OS window.
The source of the problem is that different Parallels Tools versions appear with each new version of Parallels Desktop.To solve this problem:

• Start Windows in the Safe Mode (Press F8 key (F8+Fn) during the boot-up process and choose Safe Mode from the list).
• Uninstall Parallels Tools. To do this click Start – Control Panel – Add or Remove Programs.
• Reboot Windows in normal mode.
• While Windows is running, install Parallels Tools again. For this choose Install Parallels Tools from the Actions menu in the Mac menubar. The installation Wizard will lead you through the process.
• Reboot Windows again.

How do I know if Parallels Tools are properly installed?
Double-click the Parallels icon on the Windows system tray (next to the time) to open Parallels Tool Center. It will display a list of Parallels tools. If Parallels tools are installed properly, each tool’s status will be “Enabled.”

Note: If you don’t see the Parallels icon in the system tray Parallels Tools may be not be installed. Click Install Parallels Tools from the Actions menu on the menu and follow the prompts.

How to fix it:

• Tools are corrupt after auto update and install tools.
• Go into safe mode and uninstall tools.
• Completely uninstall P and download the update from the website
• Uninstall program located in the auto update file.
• Go to website and download the DMG package. Reactivate with your current activation key.

Can I run my guest operating system on a separate hard drive?
Yes. Guest operating systems can be stored on any hard drive – including external USB 2.0 and firewire drives – as long as OS X has full read/write permissions for that drive. OS X and Parallels Desktop for Mac must be installed on your Mac’s primary hard drive.

Why are files sometimes missing when I open my Windows virtual machine?
Not shutting down the virtual machine correctly is the most common cause of missing files. If your virtual machine is not shut down properly, it doesn’t get a chance to save its settings and store information in the appropriate folders. Imagine never filing a piece of paper from your desk - your desk would eventually overflow, and you would never find anything.

• Prevention is the key! Consider your virtual machine as a normal Windows computer, and turn it off as such.
• Select Turn Off Computer from the Windows Start menu.
• A Turn Off Computer window will be displayed. Click the Turn Off button.

Do not click the red, square, unlabeled button on the right side of you Windows window. This is the virtual machine equivalent to pushing the power button on a real computer.

When I try to open my VM in Parallels Desktop for Mac I’m getting “Configuration file <your VM .pvs file> is already used by another instance of Parallels Desktop. Do you want to override the lock and open file anyway (this action may be potentially dangerous since changes done by a concurrent user may be lost)” message. What does it mean?
This message can appear in the following situations:

• It is the second instance of Parallels Desktop for Mac running in your system, and the virtual machine is already being used by the first instance. In this case close the second instance of Parallels Desktop and open the instance that is already running. You cannot access the same VM from different instances of the program).
• You haven’t closed the Parallels Desktop for Mac properly last time you used it: restarted your Macintosh computer or force quitted the program without turning off the virtual machine). In this case, if you are sure that no other instances of Parallels Desktop are running, it is safe to answer “Yes” to override the lock.

I have important data inside the VM that I don’t want to lose if anything happens to the guest OS. How can I back up the VM?
You can back up your VM on the Mac OS X side by simply copying the VM files to some safe place. By default, these file are stored on MacHD – Users - <your user account folder> - Documents – Parallels - <VM name> folder. You can see the path to your particular VM by launching Parallels Desktop for Mac and checking File Location path for the selected VM.

I’ve heard that there are many viruses that affect Windows. Will these viruses hurt my Mac if I install Windows in the virtual machine?Parallels Desktop for Mac runs the guest OS in special virtualized environment that emulates a separate computer. This virtualized computer is as vulnerable to the viruses as a usual PC running Windows. We highly recommend that you install some anti-virus software and firewall in the guest OS.

Please keep in mind that viruses and other malicious software cannot affect Mac OS X itself, but the shared folders that are accessible from the Windows guest OS can be corrupted.

Will my particular favorite program work in a virtual machine?Parallels Desktop for Mac virtualizes generic PC hardware inside the virtual machine, and, generally, most of the PC applications, supported by the guest OS, can be installed and run in the virtual machine, but you should keep in mind the following limitations:

• VM doesn't support 3D hardware graphics acceleration, so 3D graphics rendering in the VM is only possible in software mode. Virtual video adapter is generic VESA 3.0 compatible device. Most of the modern computer games using 3D graphics cannot be run inside a VM due to this limitation.
• A video adapter emulated in a virtual machine supports only single monitor mode.
• You may notice low performance when running old 16-bit applications, DOS programs, in particular. Check if the virtual machine is running with VT-x support turned on. Disable VT-x support by clicking the Acceleration link in the main Parallels Desktop for Mac configuration window and clearing the check box for the "Enable Intel VT-x support" option.

My guest Windows Vista OS works very slow. How can I increase its performance?
You should check if the VT-x support is enabled for the virtual machine. Launch Parallels Desktop for Mac, select the virtual machine and click the Acceleration link in the Configuration page. Make sure that the Enable Intel VT-x support option is selected.

How can I improve virtual machine performance on my Mac?
Parallels Desktop uses Mac system resources according to the tasks you are running inside your virtual machine. System performance depends on your Macintosh computer’s available amount of memory (RAM). 512 MB of RAM are enough for using basic guest OS functions, but it's recommended to have at least 1 GB of RAM for running resource-consuming applications in your virtual machine. To check your Mac’s memory, choose About This Mac from the Apple menu.You should also check your VM settings to make sure that it operates at maximum performance:

1. Launch Parallels Desktop for Mac.
2. Choose Preferences from the Parallels Desktop menu on the Mac menubar
3. On the Memory tab make sure that Reserved Memory Limit is set to maximum value. This parameter indicates the maximum amount of the host system’s RAM that all the VM can use simultaneously. Click OK to close the Preferences window.
4. Click the Memory link in the VM’s Configuration page of the
5. Make sure that the Memory Size setting doesn't exceed the Reserved memory limit. It's better to set the Memory Size amount at the recommended value.
6. Click OK to close Configuration Editor.

The other possible reason for poor VM performance is some resident software running in the Guest OS (in particular, an anti-virus program).

I am running Windows Vista. Why won’t the Aero Interface and Flip Page effects work?
Parallels Desktop does not currently support the hardware accelerated graphics required to use these visual affects. Parallels plans to include this support in future versions of the product. All other features included in Vista will work normally in Parallels Desktop.