[Solved] adding vhd storage to virutalbox4.3.20

[newby]

running W7 x64 home premium with SP1 as host,
VirtualBox 4.3.20 r96997
extension pack 4.3.20 96996

when adding a VHD as additional storage to VB, (VHD-file usable on other VB's at school so I assume the file is not corrupt)
following error is displayed:

Failed to open the hard disk file D:\USB\USB Disk.zip _ Windows 7 Secure USB Disk.vhd.
Could not get the storage format of the medium 'D:\USB\USB Disk.zip _ Windows 7 Secure USB Disk.vhd' (VERR_NOT_SUPPORTED).
Result Code: VBOX_E_IPRT_ERROR (0x80BB0005)
Component: Medium
Interface: IMedium {05f2bbb6-a3a6-4fb9-9b49-6d0dda7142ac}
Callee: IVirtualBox {fafa4e17-1ee2-4905-a10e-fe7c18bf5554}
Callee RC: VBOX_E_OBJECT_NOT_FOUND (0x80BB0001)

[scottgus1]

Could be a couple of things, try taking the ".zip" out of the name, maybe the extra period is causing trouble. Or maybe the device you used to transfer the vhd is formatted FAT32 or some other such format that prevents larger than 4GB files. If the file seems full-size it may still have not copied properly - run a hash value of the vhd at the source and at the destination and see if they're the same. (free hashing programs are available on the internet, I use the sha256deep function of "md5deep" (http://md5deep.sourceforge.net/) as a substitute "FC" command for checking the copy on my backup vdi's.)

Another thing, try running Mpack's CloneVDI tool on the vhd at school and bring the vdi home. Vdi is more robust than vhd and is fully supported by Virtualbox, being the native format for disks.

[mpack]

Another possibility that springs to mind is that this might be a zip file, and not a VHD at all.

[newby]

how did you guess?
I changed the extension to .zip, unzipped it and found the real vhd.
now it works!
thanks.