20 August 2012

Missed UAC Prompts May Silently Undo Installs

This is a more generic issue than what can go wrong with AVG installation, but not the usual user account rights issue.

Windows 7 makes UAC somewhat less obtrusive in various ways, which is generally welcome – but a side-effect can be to silently undo a software installation. 

What happens:

  • you start an installation
  • you aren’t prompted for admin permission
  • you leave the install process to run unattended
  • a UAC prompt pops up while you’re away
  • In Windows 7, this is now a discreet flashing item on Taskbar
  • the UAC alert is ignored, times out and assumes “no”
  • the installation is silently aborted
  • you think the installer completed OK
  • then you find your new software’s simply “not there”!

I notice this in particular with LibreOffice, where the expected UAC prompt only appears quite late in the installation process. A possible factor may be renaming the installation executable (e.g. from “Setup.exe” to “NameOfApp.exe”), as this may defeat Windows recognizing it as an installer requiring administrator rights, and thus prompting early for permission to continue.

LibreOffice is an object lesson in why Open Source may be more useful than just being free of charge.  When Oracle took over Sun and cut off the salaries of the Open Office development team, the code itself was beyond their reach – so the product could survive, as continued by the same coders working elsewhere.

One beneficial side-effect of leaving Sun, was a move away from Java, for which Open Office was something of a “poster child”.  LibreOffice is already faster to start up (even without the “quickstarter”) as a result.

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