WinMount writes VDI files (VirtualBox virtual hard disk files)

I was having extraordinary difficulty copying a 4GB file from my host to a virtual machine.

VirtualBox shared folders weren't working (client add-ons unable to be installed).

Windows file sharing, which usually did the trick, had frozen due to my host getting its nappy in a knot, and rebooting wasn't a suitable option.

I had IIS (a web and FTP server) on my host, and tried sharing the file through that, only to discover that just over 2GB into the transfer, the transfer froze - obviously a bug with something somewhere using a 32-bit signed integer and dying at the moment the transfer reached the highest number that can be represented in 31 unsigned bits.

I tried copying the file onto USB external hard disk, then mapping the external hard disk to the virtual machine via VirtualBox's USB mapping, but that too caused much grief and many hangs (not complete system hangs, but VirtualBox hangs).

I did finally, FINALLY, manage to get it to work.

I created a virtual hard disk using the VirtualBox media manager. I happened to use an auto-expand disk so that it would only use as much of my host's storage as required.

I then tried a trial version of the commercial WinMount program. It happily mounted my auto-expanding VDI virtual hard disk, mapped it to a drive letter, and I was able to copy my huge file onto the virtual hard disk.

Then I exited WinMount, mapped the virtual hard disk as a secondary disk to the virtual machine I was trying to transfer the file to, rebooted the virtual machine, and voila, I was able to copy the file from the temporary second virtual hard disk onto the virtual hard disk I wanted it to be on.

VERY convoluted, but we got there.

One weird thing : Norton "security advisor" (or whatever it's called) warned me that the WinMount website is a known source of viruses and/or trojan horses. So, I dunno, my computer might be laced with baddies now. But even though Norton warned about the website, it didn't complain about the WinMount program itself.

In short, if you're wanting to mount a virtual hard disk for read/write access in Windows - especially if it's an auto-expand virtual hard disk - WinMount commercial edition seems to do a very nice job. And it was the only tool I found that even claims to support writing to auto-expand virtual hard disks. So it seems the authors of this tool have managed to accomplish something pretty special.

But of course, don't use it in read+write mode on a virtual hard disk you can't afford to lose, just in case it busts it! i.e. if the virtual hard disk is dear to you, then make a backup before trying ANY 3rd-party tool that purports to provide read+write access! Or so I advise. :o)

Thanks WinMount - I'm puzzled by the virus/trojan warnings, and your on-screen instructions are slightly Chinglishy, but aside from that, your product seems to be very good indeed.