Installation Package Could Not Be Opened on Win 10

I’m trying to install Duplicati on my Dell XPS 15 laptop running Windows 10 v1903.
I downloaded duplicati- from the official page but all I get is this message:

This installation package could not be opened. Contact the application vendor to verify that this is a valid Windows Installer package.

What could be the issue here?

Best regards,

Hi Anton, welcome to the forum!

Have you checked the MD5/SHA hashes so you know the downloaded file is complete and unchanged?
You can get the signatures from here:

For hash computation, I use Hash Tool by DigitalVolcano Software, installed from the Microsoft Store.

Easy basic checks include checking browser download status, and checking file size in File Explorer. Currently, .msi size seems to be running about 15 MB, i.e. 15,xxx KB in Size column. Seeing 0 is bad.
Hovering over the file should also show some basic info, similar to doing right-click Properties Details.

This installation package could not be opened message in Windows 10/8/7 gives further things to try.

Video: Checking the Digital Signature of Windows Executables is a deep dive into signature checking answering some things not often clearly shown, such as using it to check for corruption or tampering.

Hopefully the solution to your installing will be found somewhere near the top of this list of things to try.