No problem on our end. Try running the installer as Administrator and make sure no files are open.

@TwentyStudi

Sorry, I've tried but still can't install the content package. I'm using Unreal Engine Version 4.26, can it affect the installation problem?

No, that shouldn’t matter. You still need to install the Aximmetry UE4 editor and cook your projects in that of course. What exactly is the problem? Did you uninstall the previous version first?

@TwentyStudios:

That's right, I uninstalled the previous version of Aximmetry, just tried to download the latest version, and when I installed an error, please help..!!

If you read the error message you can see that it’s a download error. Maybe try turning off the Windows Firewall? You could also download the asset libraries separately and install them manually.