Hi Andrew
I think this might be because the name and location of the plug-in folder has changed in SN8 but Bob's installer still tries to write to the location of Starry Night 6's plug-in folder, which no longer exists, and Windows security prevents the creation of a new folder at the old location.
You can try this workaround, it is a bit clunky but will get you the ACPPlan.plug file on to your desktop and then you can move it to the appropriate folder in SN8.
1. Download the free MSI viewer from Microsoft Store:
https://www.microsoft.com/en-us/p/ms...ot:overviewtab
2. Open MSI viewer and click "Choose" at the top right of the window.
3. Navigate to the location of your ACP Planner installer file: ACPPlanner-4.2a-Setup.msi and click "Open"
4. Scroll down the file list, select "ACPPlan.plug" the directory shown currently is SourceDir\Starry Night 6 Folder\Sky Data\Plug-ins.
5. Click the "Extract" button at the bottom right of the window then navigate to your desktop and create a temporary folder there and then "Choose" to extract the ACPPlan.plug file.
6. Open your temporary folder and inside you will find a sub-directory called "SourceDir" open that directory to find a sub-directory called "Starry Night 6 Folder", open that directory to find a sub-directory called "SkyData", open that directory to find a sub-directory called "Plug-ins" and there finally you will find "ACPPlan.plug".
7. Move that file "ACPPlan.plug to the SN8 Plug-ins folder.
I can't help with the SN8 bit as I don't have a copy but hopefully that part should be described in the SN8 help, if you get stuck post a reply and hopefully some other user here will be able to help with that bit.
If you can't obtain the plug-in using Microsoft's free MSI viewer then I could put a copy of the plug-in in my dropbox and post you a link via PM but I would prefer that you try the MSI viewer first as you can be sure that the file is virus free when sourced from your own ACP Planner installer.
Let us know if that works for you.
HTH
William.