Not able to merge files

[pennerman]

First of all I would like to preface this by saying I am running this through a virtual machine on an Appendix Silicon Mac.

I cannot select a folder or multiple files for that matter. I have multiple files that I would like to combine to one but it does not allow me to select more than one file.

[itsdinkd]

Parameter name: startIndex at System.String.Substring(Int32 startIndex, Int32 length) at NSPsplitty.MainWindow.CopyUnsplit()