I previously asked for help on this topic but that thread was closed after 90 days so I can’t post there. However, I found the problem and I’ll describe it here in case others might benefit from this info. The problem was (still is) that KiCad reports, on opening a project, that it cannot remove the ;___kicad_pro.lck’ file. The full error message looks this this: “File ‘------.kicad_pro.lck’ couldn’t be removed (error 32: The process cannot access the file because it is being used by another process.)”. I’ve discovered that the problem occurs when using KiCad while Dropbox is running in the background. KiCad apparently sees that Dropbox is another process that’s holding the ‘.lck’ file “OPEN”. That file isn’t exactly OPEN but I suppose Dropbox makes it appear that way to KiCad, so KiCad reports error 32. If you don’t want to see that KiCad error, just momentarily suspend Dropbox’s background “sync” operation.