Problem with Windows 7 guest on Yosemite (VirtualBox 4.3.22)

[pjbeee]

UPDATE March 2, 2015 - VMWare guest now experiencing similar issues with the same configuration as described below, and on more than one Mac - still investigating the issue, but I'm pretty sure it has to do with the change to Yosemite (and not sure why the problem would suddenly rear its ugly head after seeming stable under VMWare). As noted, these were native Yosemite installs, not upgrades.
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I've been successfully running a Windows 7 x64 guest under OS-X for at least 2 years, specifically for a Visual FoxPro database corporate database app; the database and program files are on a Windows 2003 server. The main FoxPro executable is copied to the Windows 7 boot drive before the app runs. Unfortunately the app has been experiencing repeated crashes with this latest combination of Yosemite/VirtualBox (v4.3.22)/Windows 7, while the Windows guest OS and Yosemite seem otherwise stable before and after the app crashes.

I have now tried this app with both Windows 7 x86 and x64 guests, with very similar results. Needless to say, both Windows 7 x86 and x64 native OS machines (no VirtualBox or other OS in sight) running the FoxPro app have no issues with the app.

This was with a fresh Yosemite/VirtualBox/Windows install. I first tried the x86 version of Windows 7, but upon reading about various bugs with this combination, I installed the x64 version.

I also tried various suggested patches to Windows, disabling SMB v2 and v3, and changing some oplocks settings, with no success. I even downgraded VirtualBox to 4.3.20 with no change.

I finally downloaded a trial version of VMWare Fusion 7, base edition, imported the same running VirtualBox Windows 7 x64 guest instance into Fusion (using the running Windows version + the VMWare Migration Agent). After a full day and 1/2 of use, so far, the user has experienced no application crashes of any kind. By this time with VirtualBox, the user would have experienced many app failures.

I am simply reporting this, and don't need a fix anytime soon. VMWare Fusion is inexpensive enough that my client will happily pay for it at this point.

My only other comment is that, aside from a few guest tweaks to VirtualBox, such as: setting memory allocation (leaving processor count set to 1 and using the default chipset), setting the network to a Bridged Ethernet adapter, and taking the defaults - letting the guest run as a DHCP client for its IP address, I did nothing special to the VIrtualBox configurations for older OS X host + Windows guest installs (under which the app ran fine right away) or to the VirtualBox config for the Yosemite version of OS X.

My suspicion is that something in Yosemite is not playing nice with VirtualBox, but I can't tell you where.

Several VirtualBox log files from one full day are attached.