Here's what's happening: when I try to install ScreenConnect, it says 'Accessing the feature', then the installation stops, then says 'Click OK to try again, or enter an alternate path to a folder containing the installation package setup.msi in the box below.' If I click OK, it says, 'The file 'c:\users\administrator.server\appdata\local\temp\' is not a valid installation package for the product ScreenConnect Client (hash number). Try to find the installation package 'setup.msi' in a folder from which you can install ScreenConnect Client (hash number).'

When I looked in the ..appdata\local\temp\ path, setup.msi is there and I've tried to execute it, but the result in the same. If I uninstall ScreenConnect client from Control Panel I get the same error. So, I can't install because it's asking me to 'try to find the installation package' and if I uninstall I get 'try to find the installation package' error. Argh!

How to Fix: ScreenConnect Will Not Install 'Package Installation' Error

What I found is that if you clear the registry of the previous ScreenConnect client, then reinstall ScreenConnect, uninstall it, then reinstall it again, it should work. I suspect that this method should fix similar errors where ScreenConnect will not install.

To do so:

1. On the machine you wish to install the ScreenConnect client, launch regedit (click Start, then type in "regedit" [no quotes] and hit Enter).
    
2. Navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Classes\Installer\Products\ and expand the list. Look at the subkeys (folders) for anything to do with ScreenConnect, and carefully delete the folder. Since each ScreenConnect installation number is different, I can't give any specifics on which subkey is the one you want to delete. You will have to look the registry values, making sure not to delete the wrong one (hint: make a backup of the registry, first!).
    
3. Proceed to install the ScreenConnect client again. This will effectively overwrite other entries in the registry pertaining to ScreenConnect. At this point you will notice that the ScreenConnect client still isn't active on the client machine - which is why you need to follow the next step.
    
4. Go to Control Panel -> Programs and Features and uninstall the ScreenConnect client again. This time it will properly uninstall the previous installation.
    
5. Reinstall ScreenConnect client again. This time it should work and you should see ScreenConnect in the tray bar near the clock.

ref: https://www.infopackets.com/news/10670/how-fix-screenconnect-will-not-install-package-installation-error#:~:text=Go%20to%20Control%20Panel%20%2D%3E%20Programs,tray%20bar%20near%20the%20clock.