Can't install v4.2.0.1671 x64

[Omega5]

I can't install v4.2.0.1671 x64. When I try to install I get an "Error opening file for writing: C:\Program Files\MultiCommander\MultiCommander.exe" with the following options: Click Abort to stop the installation,
Retry to try again, or Ignore to skip this file. Clicking on Retry and Ignore doesn't work.

Before trying to install this version a prior version was uninstalled and I think that uninstall may have failed.

How can I fix this?

[Mathias (Author)]

If the uninstaller failed it can be because of that.

The uninstaller probably failed because MC was already running (or something else was locking the files), and if MC was running then the installerer can not replace the file.

Make sure MultiCommander is not running and that the uninstaller removed the files in  C:\Program Files\MultiCommander\
Or just use the MultiUpdate to update instead of doing a reinstall..(but if you already uninstalled that program might be removed.)

[Omega5]

The folder,  C:\Program Files\MultiCommander\, was removed during the uninstall but when I try to install again I get a message that "MultiCommander is already installed. Do you want to uninstall the existing version." When I click Yes I get the message "Try to install Multicommander again?" When I click Ok the message repeats: "MultiCommander is already installed. Do you want to uninstall the existing version." The install process is stuck in this loop.

[Mathias (Author)]

That is because it was not uninstalled correct and it is still registered inside Windows as a program that is installed
(So it will be shown in "Programs and Features" window where Windows list all installed software. )

Remove the registry key

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\MultiCommander

or

HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\MultiCommander

(depending on what kind of installation you had, Single User or All Users)