VB 4.2.10 Can't Mount Guest Additions ISO Image

[saberman]

Host: Windows 7 Ultimate X64
VB 4.2.10
Guest: Windows 7 Ultimate x64

I upgraded VB 4.2.2 to 4.2.10. I then started a VM and logged in as an administrator. I then tried to install guest addtions. However, the virtual DVD drive did show the CD -- it was as if nothing was mounted. I tried other ISO images and they could be seen.

The iso file is dated 3/5/2013 and is 65,058 KB.

Is there something worng with the 4.2.10 guest addtions image?

Edit: If I mount another ISO image and then try to mount the guest additions nothing happens. IOW, the first ISO image remains in the drive.

[mpack]

Please adjourn to v4.2.10 discussion topic.