Postgresql 11.5 installation problem

It appears that the root cause of this issue may have been that @Celeritas's computer had an incorrect value for the COMSPEC environment variable. It had a trailing semicolon, so instead of the normal:

C:\Windows\system32\cmd.exe

it was:

C:\Windows\system32\cmd.exe;

This one-character difference is enough. The above isn't a valid command prompt path, so popen() calls were failing. Unfortunately, instead of something useful like:

'"C:\Windows\system32\cmd.exe;"' is not recognized as an internal or external command, operable program or batch file

it instead reports the delightfully useful error No error:

initdb: could not execute command ""C:/Program Files/PostgreSQL/9.2/bin/postgres.exe" --boot -x1 -F ": No error

See related:

• http://forums.enterprisedb.com/posts/list/2125.page
• http://postgresql.1045698.n5.nabble.com/initdb-failure-td2083455.html

I've reported this to the installer team and written a wiki entry to describe it. See blog post.

The issue was eventually resolved by:

• Editing the COMSPEC environment variable
• Uninstalling PostgreSQL
• Rebooting
• Reinstalling PostgreSQL

though there was a lot more before that which shouldn't actually be necessary to resolve this, including doing a total manual clean uninstall of PostgreSQL by hand.

Now I just want to find the people who wrote the program that modified this environment variable.

I was having this issue on Windows 7 64-bit and the following solution is what worked for me (via http://igordcard.blogspot.com/2012/03/unable-to-write-inside-temp-environment.html):

Why
To understand why this error was happening, I went to my TEMP folder and read the log from the PostgreSQL installer: C:\Users\myuser\AppData\Local\Temp\bitrock_installer.log

Which mentioned an interesting detail:
Input Error: There is no script engine for file extension ".vbs".

So, I picked up another file from the TEMP folder, the actual script used by the installer:
C:\Users\myuser\AppData\Local\Temp\prerun_checks.vbs

And tried to run it through the console using cscript:
Input Error: There is no script engine for file extension ".vbs".

I researched a bit more and discovered that the type of file associated with the vbs extension had been changed. In my case, by Notepad++. After I installed Notepad++, I associated some file extensions with it (including vbs), thus causing problems when detecting the type of the script (which shouldn't happen).

Solution
Run regedit, navigate to HKEY_CLASSES_ROOT\.vbs and change the (Default) key back to the string VBSFile. In my case it had been previously altered to Notepad++_file.