The system corrupts

An update is due again, as it always is. This time it is the digital signage program Dise. Previously deployed version is 1.6 and when I try on my lab computer both uninstalling this version and installing the new one works beautiful with just a /S switch. A good five minutes of work that I can charge $500 for. I can lean back, take a sip of coffee and browse the internet for "news".

I deploy the application but curiously I don't get any statistics in System Center, nothing seems to happen. Suddenly I hear screaming. The staff at the call center seem distressed. I find that after a restart the computers don't boot anymore, all thats left of our entire environment is this:

It turns out that uninstalling Dise 1.6 with the SYSTEM accound wipes the boot sector for no reason. The computer is now a brick.

Fortunately the above scenario didn't play out, because I actually spent more than five minutes and caught this before deploying.

Many installs behave differently when installing as SYSTEM as opposed to an ordinary administrator account. Every install MUST be tested with this account before being deployed sitewide. I recommend at least having a CMD shortcut on the desktop that uses psexec.exe to launch as SYSTEM.

Some old issetup.dll, a component in Installshield built setups, had a bug that launched the install as the currently logged on user, which of course failed with tons of access denied. Some installs deploy settings only to the running users profile, which in this case is C:\Windows\System32\config\systemprofile or might fail to write user settings altogether. Some installs get confused for other reasons when the environment is different from a standard user.

Few installs are as awful as Dise, but there are more ways to completely destroy a computer. More about that in a later post.