The guts of this post were added to another thread, but the problem has persisted so I thought I'd start a dedicated thread for it. * * * I upgraded to 5160 yesterday and since then I've had a couple of problems. I have two VMs running on my nearly new Mac Pro with 5Gb RAM, a Vista installation and Debian Linux. The first problem seems to have sorted itself out. After the upgrade the Linux VM had real problems starting. Running Parallels seemed not pause at the configuration screen and would attempt to boot Linux without my asking. It also added a series of "1"s to the name of the VM. Not sure why. It did the same on my Vista VM too and I had to edit the name by deleting the "1"s when things had stabilised. For example the Linux VM was suddenly called "Debian Linux 1 1 1 1 1 1 1 1". A hard reboot of the Mac Pro (a rarity for me and a reluctance) appears to have sorted these issues out. The other one continues and seems to affect the Vista VM only. Six or so times now I've left the VM running and the mac has idled for a period of time (more than 15 minutes, less than three hours). I'll come back and Vista will be displaying the login box. It is rebooting itself after a BSOD. After logging back in I get a message about a bad boot saying - 'Problem description: Blue screen.' Now, I don't really know much about Windows as I've been Mac only for years now. Usually though, if the Vista VM crashes or is just turned off it will display a Safe Mode boot option screen on restarting. Obviously if I'm seeing the login screen it's bypassing that (or timing out and booting the default?). Maybe it's behaving like the Mac 'reboot after power failure' option? Whatever is happening, extended idle time is causing Windows to crash and restart. Other than at idle time the VM seems to run well in all modes and there are no other issues apparent at the moment. I have tested and the crash/reboot happens if Mac power settings are set to screen off after x minutes or screen off never. I've tested sending the mac to full 'sleep' with the VM running Vista and Linux and both restore ok on waking up. This reboot problem only happens when the machine sits idle, not when the Mac is sleeping. Sometimes, but not every time, returning to wake the screen up will see the Vista VM 'paused' and a Parallels message asking if I want to un-pause it. When this has happened I myself haven't paused the VM. My VM files are in the default location within my home directory 'Documents' folder. This happens to be on a second HDD in the machine which does seem to spin down despite the OS X Power Saving preference pane being set not to 'Power down hard disks where possible'. Is it possible to relocate my Parralels folder and point the app to the new location? One thing I changed after the 5160 upgrade was increasing the Windows VM memory allocation to the max 2Gb. I may switch that back to 1.5Gb and see if it stabilises. Any ideas or similar stories much appreciated. Mark. ---- My machine is a 2x 2.66 Dual-Core Mac pro with 5Gb RAM. It's running a fully up-to-date Tiger 10.4.10.