I am running a development environment that uses VirtualBox but I am not sure where the problem lies. Host: Windows 7 Ultimate x64 Guests: Windows 7 Ultimate x64 The host has a locally attached drive that has the root shared with a share name of Install. Everyone has read access and Authenticated Users have full control. Each of the virtual machines maps \\<host machine name>\Install to I:\ Using virtual machine VM_A I edited a group of .png files to document an issue and saved them, one at a time to I:\Transfer\<file name> I then switched to virtual machine VM_B and open a new Outlook email message. Then I opened explorer and the I:\Transfer folder. The .png files were not visible. I tried refreshing the display (F5) a number of times. I tried using I:\Transfer\<file name> to reference one of the them and got a file not found message. After bouncing between the virtual machines the files suddenly appeared to VM_B. I have had this happend before with Excel spreadsheets and other file types. It looks like the disk buffers are not getting flush to the mapped drive in a timely fashion. Is it possible for buffer flusshing to be delayed that long?

Hi, This is not a real network issue. It is related to the mechanism of file transferring inside VirtualBox. I suggest you discuss in VirtualBox forum for more information. VirtualBox on Windows Hosts Important Note: Microsoft provides third-party contact information to help you find technical support. This contact information may change without notice. Microsoft does not guarantee the accuracy of this third-party contact information.Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.

> I suggest you discuss in VirtualBox forum for more information. I already did and they said that as long as I was not using VirtualBox's shared folders -- which I am not -- it is a Windows 7 issue. The files were editted on at a time in MS Paint and saved to the mapped drive. The drive in question is a real local drive on the host not a virtual hard drive. The VMs use regular Windows 7 disk mapping to attach the drive. VirtualBox is simulating the network adapter. Windows 7 is handling all of the disk I/O and buffering. MS Paint saved the files to disk. The network redirector should have routed the data through the virtual network adapter to the host as though it came from the host's network adapter. The only thing VirtualBox is involved in during the process of saving a file is transfering packets between the machine writing to the file (VM_A) and the machine that the drive is attached to -- the host. Then transfering packets between the host and VM_B. Unfortunately, I did not check to see if the host -- the machine with the local drive attached -- could see the files. So I don't know if the problem is between VM_A and the host or between the host and VM_B. The problem only occurs once in a while. Most of the time I can save a file to the mapped drive on VM_A and immediately see it on VM_B. I am using Micrsoft's Security Essentials package on the host and both VMs. However, it is set to scan at 2:00 AM on Sunday's so it was scanning at the time. The files are relatively small so the real time protection should not have slowed them down very much -- certainly not minutes.