Hello and welcome to PixInsight Forum.
These are the steps to download and install PixInsight:
1. With your username and password, log in our software distribution system:
https://pixinsight.com/dist/
2. Download the installation package(s) for version 1.8.8 corresponding to your platform(s): FreeBSD, Linux, macOS, or Windows.
3. Uninstall the version of PixInsight you have currently installed, if you have one:
FreeBSD and Linux: Do nothing; the installer program removes an existing installation automatically.
macOS: Move the /Applications/PixInsight folder to trash (known as 'bin' since macOS 10.15).
Windows: Use Control Panel or 'Add or Remove Programs' to uninstall PixInsight.
4. If you are using Windows, and very especially if you use Windows 7 (which is not supported), it is advisable to reboot your computer before continuing.
5. Run the installation package. Just follow the instructions, agree with our software license, and don't change anything.
Once you have PixInsight installed, run it. If you have a valid license file on your computer, then you're done. Otherwise, for example if you still haven't used PixInsight on this machine, or if you have been using a version older than 1.8.6, you'll have to reactivate your license. In such case the PixInsight Software Activation dialog will be shown. Click the Request Activation Codes button and follow the instructions given. You'll have new license activation codes in your inbox in a few minutes.
Version 1.8.8-1 is being distributed as an update. You'll receive it directly from our distribution server after installing 1.8.8, along with additional updates to scripts, tools and documentation.
