What is this file _Setup.dll doing in the installation folder?

During and after installation, the Setup.exe program creates a number of files on the target system to support various features. In general, these files are automatically removed when your application is uninstalled, but we list them for completeness.

Files in <AppFolder>

In addition to your own application files, you may find the following files in the <AppFolder> installation folder after installation. Note that most of these files are marked Read-only, Hidden, and System, so they may not show up in your Windows Explorer window.

Setup.exe The installer and uninstaller executable. This file is always present; without it, your application cannot be uninstalled.
Setup.ini The installation and uninstallation database. This file is always present; without it, your application cannot be uninstalled.
_Setup.dll The satellite DLL that contains the resources for the selected installation language. This file is only present if the installation language is something other than US English. Without it, Tarma QuickInstall uses US English.
_Setupx.dll The extension DLL, if your installer uses any.
_Setup1.bmp The bitmap file for the Welcome bitmap if your installer uses custom graphics.
_Setup2.bmp The bitmap file for the page headers if your installer uses custom graphics.

Files in <TempDir>

The following files are created in the target system's <TempDir> folder.

package.log The installation log file. package is the file name of your installation package. If you check the Clean up log option on the Installation page, this file is automatically removed after successful installation.
Setup.log The uninstallation and registration log file. If you check the Clean up log option on the Installation page, this file is automatically removed after successful uninstallation.
_TinDel.exe This is a small (1.5 KB) helper program that is used for some final cleanup actions when your application is removed. It is removed during the next system restart.