Can't update guest additions for one vm

[hangerglide]

I run vbox 4.2.6 on a win 7 pro machine. I am prompted to install the current guest additions each time I boot it (it says it has 4.1.16). However, when I choose install guest additions from the menu, nothing happens. It was doing this before I recently updated to vbox 4.2.6. Other similar vms on this host have been updated to the current ga without issue. How can I fix this?

[mpack]

All that "Install Guest Additions" does is mount the VBoxGuestAdditions.iso CD image in the VM. What happens next depends on how the autorun feature of the guest OS is set. If disabled, nothing will happen - in which case you need to browse to the virtual CD inside the guest and manually run the installer executable. I would tell you which file to run, but you neglected to mention what the guest OS is. In any case it's probably obvious.

[hangerglide]

Thanks that makes it clear. vm guests is windows 7.

[mpack]

In that case you would run the .exe file you see in the root folder of the CD.