VBox Guest Addition 6.1.32 install fails on Ubuntu 20.04.4 in Win7 Ult 64 bit

I have a 64 bit Win7 Ultimate guest VM installed on 64 bit Ubuntu 20.04.4 LTS box. Install of the Guest Additions for 6.1.32 VBox fails with "ERROR (800b0100) No signature was present in the subject".

A msg at the top of the install dialog says "Installation Aborted. Setup was not completed successfully."

Any suggested fixes/work arounds? The VM is completely useless without access to the host file system. The postage stamp display is no panacea either.

1 Answer

This issue is generally caused when Windows Defender doesn’t like something in the .msi that is being installed. There are three possible solutions to this issue:

1. Disable Windows Defender (and any other anti-virus mechanism that might be running), then try the installation again
2. View the Guest Addition files with Explorer, then run the installation .exe manually (e.g.: VboxWindowsAdditions-x86.exe)
3. Install an older version of the Guest Additions. I have found the 6.1.0 ISO to be the most reliable on older Windows clients such as Vista and Win2K. The guest additions version does not need to match the version of VirtualBox, though it is usually better when they do.

Hopefully one of these will work for you.