OTTD 1.8.0 doesn't work!

[jfs]

It's arguably a bug in the installer, if it doesn't throw an error if one or more required files can't be written.

[dadyo]

I'm fairly sure every installer in the history of installers told you to quit all running programs before continuing

The installer tells 'It is recommended that you close all other applications...'. But if you forgot you have OpenTTD running in another desktop, it doesn't show up in your taskbar (on Win 10, that is) so it is easy to forget.

It's very easy to reproduce (install 1.8.0 while 1.7.2 is running). Step by step:

Cleaning current set up
- Uninstalled openTTD with uninstaller.
- Checked C:\Program Files, no openttd folder anymore

So from clean set up:
- Installed 1.7.2 with openttd-1.7.2-windows-win64.exe (file version 1.7.2.1)
- Now C:\Program Files\OpenTTD\ is there with openttd.exe of 24-12-2017
- Started it once, having startscreen running and not closing it.
- Started install 1.8.0 with openttd-1.8.0-windows-win64.exe (file version 1.8.0.1), it says 'Welcome to OpenTTD Setup. This will allow you to upgrade from version 1.7.2.'
- After install (no warnings nor errors) I start openTTD and get the error 'No available language packs (invalid versions?)'. And openttd.exe still is date 24-12-2017.

After stopping the running 1.7.2 and installing 1.8.0 again (don't have to delete all first) it runs good (and openttd.exe is of 01-04-2018)

[jfs]

I made a bug report on the issue tracker for this now: https://github.com/OpenTTD/OpenTTD/issues/6884

I'm not versed in the NSIS installer system so I hope someone else will know how to fix this.