VMware guest pauses when the host is idle - how do I keep it running?

I'm running VMWare Worstation 7 with Windows 7 x64 as guest, Windows XP x64 as host. Inside the guest I run a long-running console application, which prints out progress messages with timestamps on them. Sometimes I leave it running for several hours while I lock the host OS and don't touch the computer at all. When I come back I find that some time after I left it seems to have paused and automatically resumed: the console app hasn't made much progress and there's a large time gap in its progress messages.

There's nothing relevant in the host event log, but in the guest Application event log I can see these messages around the time I left:

A request to disable the Desktop Window Manager was made by process (VMware Tools Service)

The Desktop Window Manager was unable to start because composition was disabled by a running application

And later, around the time I returned, this shows up in the System log:

The system time has changed to ‎2012‎-‎01‎-‎12T06:36:46.921000000Z from ‎2012‎-‎01‎-‎12T03:18:19.953079000Z.

That seems to support my theory that it's VMware doing something and not Windows itself. The question is: how do I stop it doing that? I want my application to continue running. By the way, the power options are set to never sleep in both guest and host.

Disabling the vmware service will stop it, because you are disabling the communication between the guest and the host. The sleep signal sent from the OS (which is where it originates) is translated through vmware tools, to a pause command. Stopping the service will also compromise all the features of vmware tools like freeing up the memory and other important aspects of running the vm in vmware and performance of the host will suffer.

To solve your problem, go to power settings in windows (right click desktop > personalise > screen saver > power management) and change when your computer goes to sleep. that is all is happening, the default settings for windows 7 is to sleep after 30 mins. This is being sent to the host via vmware tools, which is why disabling the service worked. but that is a real bodge, just change it to 'never' sleep/always on.

In VMWARE tools go under the scripts tab, and you will see a script event that probably says 'Suspend Guest operating system'. Untoggle 'Use Script', and that should stop the VM from suspending on its own. I had the same issue and your suggestion about vmware tools tipped me off where to look.