Bill.

Have Maxim DL open, DL6 or DL7, both still work with planner, start ACP Planner and delete any plans currently showing in the Target list, open Tools > Preferences, make sure that in the box 'Imager Characteristics' you have the check box selected for 'Multiple filters' then click the 'Get From MaxIm' button to upload the filter names directly from MaxIm.

When the check box 'Multiple filters' is deselected in Pref's then you can't import from MaxIm, and you can't import old plans that have filters assigned (AFAIK).

Review your other Planner Pref's and click the 'OK' button to save and see if that fixes the problem.

Provided Planner now works as expected, and once you have the Pref's setup as required, be sure to use the 'File' > 'Save Observatory Profile' and export the current Planner profile to a removable drive for recovery after a system crash.

I can use Planner here with Windows 11 Pro 24H2 and MaxIm DL7, and despatch a plan to ACP, although it's not a tool I use much these days.

William.