App-V 5.1 sequencer fails to install with fatal error

Lat week I was asked by one of my friend to troubleshoot an issue which he was facing earlier.

Question: When Installing App-V 5.1 sequencer, it fails to install with the below error.

 

Solution: When Installing the sequencer, it places log files in %temp% location. We can analyze the possible reason by looking into it.

When opened the appv_sequencer_xxxxx_0_CoreX64 log file (which is the actual MSI install log), and Ctrl+F search and giving Return value 3 we see that there is a pending restart needed before installing the sequencer. The sequencer msi has a Launch condition to check for any pending restart.

We restarted the machine and again tried to install the App-V 5.1 sequencer setup. this time it got installed successfully.