I have a Linux guest VM in VirtualBox and if I leave it sitting for a while, e.g. >1-2 hours, often when I come back the guest UI is partially frozen. I searched this site for these symptoms and most of the other threads involved either a particular scenario of events freezing things (e.g. accessing items in folder shared with host), or total freezing of the system.
In my case it's a partial freeze. For example, I just let my guest sit idle for about 2 days. When I left the machine, there was one terminal, one file browser, and one gedit running. The focus was on the Terminal.
When I went back to it just now, the login screen was showing, and I was able to login fine (not not 100% frozen). I can still interact with the terminal by keyboard, and successfully run terminal commands. This suggests to me that core OS things like file I/O and Kernel are still running OK. However, I can't change focus to any other windows or do anything else in any other part of the OS GUI, nor can I really do anything with the mouse.
E.g. if I try to click on another window, there is no focus change or effect on that window. I cannot click "Applications", "Places", etc. I cannot even highlight text in the Terminal window that is working, I can only type in it.
The following screen grab highlights this behaviour (yellow box added by me to cover up some SW code):
Some other things to note or that I've tried:
- The display has stopped auto-resizing. E.g. if I full screen (Right CTRL+F), VBox goes full screen, but the guest OS doesn't pick up the resolution change and stays the same size, so it gets letterboxed.
- I can save the Guest state from VBox Manager UI and restart it, and it comes back in the frozen state. I saw discussions where this helped b/c just the VBox display was frozen. Doesn't help me though.
- Shutting down the Guest from VBox Manager works, and the guest recovers fully, i.e. no longer frozen, after restart.
- The severity of freezing varies with how long the guest was idle. E.g. if I just leave it for a couple hours, sometimes it's fine, other times I can still switch window focus and do things in other windows, but can't move or resize any windows or click the OS menus (Applications, etc.).
- Host specs: Windows 7 Enterprise 64-bit with Core i7-4790, 32GB RAM, VT-X enabled.
- Guest specs: Red Hat (CentOS 6.x) 64-bit, 4GB RAM, 128MB Video Memory.
- VirtualBox details: Version 5.1.8 r111374 (Qt5.5.1), and I think I have the latest Guest Additions installed in Guest (can't remember the version but I do have a folder shared with Host which requires GA).
