Someone hit this exception which was posted to the Exceptions list:
https://skyline.gs.washington.edu/labkey/announcements/home/issues/exceptions/thread.view?rowId=7719
Exception type: System.ArgumentException
Error message: An item with the same key has already been added.
Stack trace:
at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
at pwiz.Skyline.SettingsUI.EditPeakScoringModelDlg.TargetDecoyGenerator.PopulateDictionary() in C:\proj\pwiz\pwiz_tools\Skyline\SettingsUI\EditPeakScoringModelDlg.cs:line 1106
at pwiz.Skyline.SettingsUI.EditPeakScoringModelDlg.TargetDecoyGenerator..ctor(IPeakScoringModel scoringModel) in C:\proj\pwiz\pwiz_tools\Skyline\SettingsUI\EditPeakScoringModelDlg.cs:line 1091
at pwiz.Skyline.SettingsUI.EditPeakScoringModelDlg.SetScoringModel(IPeakScoringModel scoringModel) in C:\proj\pwiz\pwiz_tools\Skyline\SettingsUI\EditPeakScoringModelDlg.cs:line 119
at pwiz.Skyline.SettingsUI.EditPeakScoringModelDlg.set_PeakScoringModel(IPeakScoringModel value) in C:\proj\pwiz\pwiz_tools\Skyline\SettingsUI\EditPeakScoringModelDlg.cs:line 107
at pwiz.Skyline.Properties.PeakScoringModelList.EditItem(Control owner, PeakScoringModelSpec item, IEnumerable`1 existing, Object tag) in C:\proj\pwiz\pwiz_tools\Skyline\Properties\Settings.cs:line 1502
at pwiz.Skyline.Properties.SettingsList`1.NewItem(Control owner, IEnumerable`1 existing, Object tag) in C:\proj\pwiz\pwiz_tools\Skyline\Properties\Settings.cs:line 2168